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Evaluation of Biodiesel Fuel: 
Literature Review 

Christopher Strong, Charlie Erickson and Deepak Shukla 

Western Transportation Institute 

College of Engineering 

Montana State University - Bozeman 

Prepared for the 

Montana Department of Transportation 

Research Section 

2701 Prospect Avenue 

Helena, MT 59620-10010 

January 2004 

Evaluation of Biodiesel Fuel: Literature Review 

Documentation Page 


1. Report no. FHWA/MT-04-001/81 17-20 

2. Government Accession No. 

3. Recipient's Catalog No. 

4. Title and Subtitle 

Evaluation of Biodiesel Fuel: Literature 

5. Report Date January 2004 

6. Performing Organization Code 

7. Author(s) 

Christopher Strong, 
Deepak Shukla 

8. Performing Organization Report No. 

Charlie Erickson and 

9. Performing Organization Name and Address 

Western Transportation Institute 
Montana State University 
PO Box 174250 
Bozeman MT 59717-4250 

10. Work Unit No. 

1 1 . Contract or G rant No. 


12. Sponsoring Agency Name and Address 

Research Section 

Montana Department of Transportation 

2701 Prospect Avenue 

PO Box 201001 

Helena MT 59620-1001 

13. Type of Report and Period Covered 

Final Report 

July 2003 - November 2003 

14. Sponsoring Agency Code 5401 

is. supplementary Notes Research performed in cooperation with the Montana Department of 

Transportation and the US Department of Transportation, Federal Highway Administration. 

16. Abstract 

This document reviews recent literature regarding the usage of biodiesel and biodiesel blend 
fuel in on-road applications. The report describes some of the principal characteristics of 
biodiesel and usage experience in and near the State of Montana. Several studies are 
summarized regarding biodiesel's effects on engine performance and warranties. Storage, 
handling and transportation requirements are also discussed. The emissions-related impacts 
of biodiesel on several pollutants are quantified, along with potential effects of these impacts 
on the state and vehicle users within the state. The legislative environment regarding biodiesel 
and existing motor fuel taxes - at a Federal level and in other states - is reviewed. 
Considerations regarding fuel cost and domestic productive capacity are discussed. The 
report concludes that most technical questions regarding biodiesel appear to be satisfactorily 
answered; the primary obstacles limiting broader biodiesel implementation relate to cost and 
user acceptance. 

17. Key Words 

alternate fuels, biodiesel, Diesel fuels, 
economic impacts, engine performance, fuel 
taxes, pollutants 

18.0 istribution Statem ent 

Unrestricted. This document is available 
through the National Technical Information 
Service, Springfield, VA 21161. 

19. Security Classif. (of this 


20. Security Classif. (of this 


21 . No. of Pages 


22. Price 

Western Transportation Institute 

Page ii 

Evaluation of Biodiesel Fuel: Literature Review Disclaimer and Acknowledgements 


This document is disseminated under the sponsorship of the Montana Department of 
Transportation and the United States Department of Transportation in the interest of information 
exchange. The State of Montana and the United States Government assume no liability of its 
contents or use thereof. 

The contents of this report reflect the views of the authors, who are responsible for the facts and 
accuracy of the data presented herein. The contents do not necessarily reflect the official policies 
of the Montana Department of Transportation or the United States Department of Transportation. 

The State of Montana and the United States Government do not endorse products of 
manufacturers. Trademarks or manufacturers' names appear herein only because they are 
considered essential to the object of this document. 

This report does not constitute a standard, specification, or regulation. 


The Montana Department of Transportation attempts to provide reasonable accommodations for 
any known disability that may interfere with a person participating in any service, program, or 
activity of the Department. Alternative accessible formats of this document will be provided 
upon request. For further information, call (406)444-7693 or TTY (406)444-7696. 


The authors would like to thank those who provided technical information that was helpful in 
putting together this report, including Jim Evanoff from Yellowstone National Park, Lou 
Summerfield from Glacier National Park, Vic Lindeburg from Grand Teton National Park, 
Howard Haines and Trista Glazier from Montana Department of Environmental Quality, Lee 
Gribovicz from Wyoming Department of Environmental Quality, John Walls from Arizona 
Department of Environmental Quality, Al Nicholson from Nevada Department of Motor 
Vehicles, and Jeff Kimes from US EPA Region 8. 

They would also like to thank those at the Western Transportation Institute who helped in 
technical review, including Steve Albert, Carla Little and Lisa Ballard, along with Howard 
Haines and others at Montana DEQ. 

Western Transportation Institute Page iii 

Evaluation of Biodiesel Fuel: Literature Review 

Glossary of Abbreviations 


AFV Alternative Fuel Vehicles 

ASTM American Society of Testing & Materials 

BOCLE Ball on Cylinder Lubricity Evaluator 

CAA Clean Air Act 

CFPP Cold Flow Plug Point 

CMSA Consolidated Metropolitan Statistical Area 

CO Carbon Monoxide 

CO2 Carbon Dioxide 

DEQ Montana Department of Environmental Quality 

DI Direct Injection 

DOE U.S. Department of Energy 

EMA Engine Manufacturers Association 

EPA U.S. Environmental Protection Agency 

EPAct Energy Policy Act 

FAME Fatty Acid Methyl Ester 

FAPPJ Food and Agricultural Policy Research Institute 

FTP Federal Test Procedure 

GCVTC Grand Canyon Visibility Transport Commission 

GHG Greenhouse Gas 

HC Hydrocarbons 

HFRR High- Frequency Reciprocating Rig 

LDV Light- Duty Vehicles 

MCA Montana Code Annotated 

MDT Montana Department of Transportation 

MECA Manufacturers of Emission Controls Association 

MoDOT Missouri Department of Transportation 

MSA Metropolitan Statistical Area 

NAAQS National Ambient Air Quality Standards 

NCOC National Carbon Offset Coalition 

NO x Nitrogen Oxides 

OEM Original Equipment Manufacturers 

PAH Polycyclic Aromatic Hydrocarbons 

PM Particulate Matter 

ppm Parts per million 

SIP State Implementation Plan 

S0 2 Sulfur Dioxide 

USDA-ERS U.S. Department of Agriculture Economic Research Service 

VMT Vehicle Miles of Travel 

VOC Volatile Organic Compounds 

WRAP Western Regional Air Partnership 

Western Transportation Institute 

Page iv 

Evaluation of Biodiesel Fuel: Literature Review Abstract 


This document reviews recent literature regarding the usage of biodiesel and biodiesel blend fuel 
in on-road applications. The report describes some of the principal characteristics of biodiesel 
and usage experience in and near the State of Montana. Several studies are summarized 
regarding biodiesel' s effects on engine performance and warranties. Storage, handling and 
transportation requirements are also discussed. The emissions- related impacts of biodiesel on 
several pollutants are quantified, along with potential effects of these impacts on the state and 
vehicle users within the state. The legislative environment regarding biodiesel and existing motor 
fuel taxes - at a Federal level and in other states - is reviewed. Considerations regarding fuel 
cost and domestic productive capacity are discussed. The report concludes that most technical 
questions regarding biodiesel appear to be satisfactorily answered; the primary obstacles limiting 
broader biodiesel implementation relate to cost and user acceptance. 

Western Transportation Institute Page v 

Evaluation of Biodiesel Fuel: Literature Review Table of Contents 


Disclaimer Statement iii 

Alternative Format Statement iii 

Acknowledgements iii 

Glossary of Abbreviations iv 

Abstract v 

Table of Contents vi 

List of Tables viii 

List of Figures ix 

1. Introduction 1 

2. Background on Biodiesel 2 

2.1. Definition 2 

2.2. Manufacture 2 

2.3. U.S. Standards 3 

2.4. Fuel Properties 3 

2.5. Regional Experience 9 

2.5.1. Yellowstone National Park 9 

2.5.2. Glacier National Park 11 

2.5.3. Grand Teton National Park 11 

2.5.4. Other Regional Users 12 

3. Engine Performance Characteristics 13 

3.1. Torque and Power 13 

3.2. Engine Durability and Materials Compatibility 14 

3.3. Fuel Efficiency 15 

3.4. Viscosity 15 

3.5. Warranties 16 

3.6. Off-road Vehicles 17 

4. Transportation, Handling, Storage 20 

4.1. Transportation 20 

4.2. Handling 20 

4.3. Solvency 20 

4.4. Stability 21 

4.5. Storage 21 

5. Emissions and Air Quality Impacts 23 

5.1. Emission Types 23 

5.1.1. NO x 23 

Western Transportation Institute Page vi 

Evaluation of Biodiesel Fuel: Literature Review Table of Contents 

5.1.2. PM 23 

5.1.3. HC 24 

5.1.4. CO 24 

5.1.5. C0 2 24 

5.2. Review of Emissions Studies 24 

5.2.1. NO x 26 

5.2.2. PM 28 

5.2.3. HC 29 

5.2.4. CO 29 

5.2.5. C0 2 29 

5.3. State and Regional Emissions Impacts 30 

5.3.1. Background 30 

5.3.2. Potential Positive Impacts 33 

5.3.3. Potential Negative Impacts 35 

6. Legislation 37 

6.1. Europe 37 

6.2. Federal 37 

6.2.1. Motor Fuel Tax 37 

6.2.2. EPAct 38 

6.3. State Legislation 39 

6.3.1. Minnesota 40 

6.3.2. Illinois 40 

6.3.3. Missouri 40 

6.3.4. North Dakota 41 

6.3.5. South Dakota 41 

6.3.6. Hawaii 41 

6.4. Montana 41 

7. Other Factors 42 

7.1. Cost 42 

7.2. Production Capacity 43 

8. Summary and Conclusions 45 

8.1. Summary of Findings 45 

8.2. Recommendations for Phase 2 Testing 46 

References 47 

Western Transportation Institute Page vii 

Evaluation of Biodiesel Fuel: Literature Review List of Tables 


Table 2-1: Feedstocks Used for Biodiesel Manufacture 2 

Table 2-2: ASTM Specifications (D6751) for B100 4 

Table 2-3: Comparison of Fuel Properties between Diesel and Biodiesel 4 

Table 2-4: Summary of Biodiesel Properties for Various Feedstocks 8 

Table 3-1: Summary of Warranties for Tractors, Since 1996 19 

Table 5-1: Source Impacts on Using Soy-Based B20 Compared to Average Diesel 25 

Table 5-2: P- Values for Biodiesel Source Effects 25 

Table 5-3: National Ambient Air Quality Standards 31 

Western Transportation Institute Page viii 

Evaluation of Biodiesel Fuel: Literature Review List of Figures 


Figure 2-1: Cloud Point as Function of Increasing Biodiesel Percentage 6 

Figure 2-2: Cold Weather Properties of Biodiesel Fuels and Blends 7 

Figure 5-1: Biodiesel Source Effects of NO x 26 

Figure 5-2: Biodiesel Source Effects of PM 28 

Figure 5-3: Biodiesel Source Effects of CO 29 

Figure 7-1: Price Comparison of Diesel Fuel vs. Canola Biodiesel Blends 43 

Western Transportation Institute Page ix 

Evaluation of Biodiesel Fuel: Literature Review Introduction 


On February 12, 2003, the Transportation Committee of the Montana House of Representatives 
heard testimony on House Bill 502, which proposed that all diesel fuel sold for use in internal 
combustion engines contain at least 2 percent biodiesel fuel by volume. The bill was discussed 
but tabled by the committee because of "unanswered questions surrounding this relatively new 
technology." Specific concerns included: 

?? "the effects of biodiesel blends on engine performance - specifically fuel economy, 
torque, and power - as compared to diesel; 

?? cold weather product storage and potential for gelling; 

?? sulfur, carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxide (NO s ), and other 
emissions; and 

?? potential for engine damage." (j_) 

The Montana Department of Transportation (MDT) was asked by the House Transportation 
Committee to initiate a research project focusing on the viability of using biodiesel as an 
alternative fuel in MDT's vehicle fleet. To undertake this study, MDT is seeking to implement 
this project in two phases: first, a review of relevant literature regarding the performance of 
biodiesel in motor vehicles; and second, a test application using a B20 blend (20 percent oilseed- 
based biodiesel, 80 percent conventional diesel) in three MDT vehicles housed in Missoula and 
three housed in Havre. 

This document concludes phase 1 of the research effort. It examines the body of literature that 
currently exists regarding laboratory and field experience with the use of biodiesel fuels, with an 
emphasis on oilseed-based biodiesel. The information gathered in this review should provide 
MDT and the State Legislature with better information to help them make decisions regarding 
the future usage of biodiesel fuels in the state. 

Chapter 2 provides an overview as to what biodiesel is, what types of biodiesel exist, and its 
principal properties. Chapter 3 reviews engine performance characteristics for biodiesel, 
including fuel economy, torque and power, and engine fatigue and damage. Chapter 4 reviews 
storage, transport and handling characteristics of biodiesel, with a specific emphasis on cold 
weather properties. Chapter 5 reviews biodiesel emissions and associated air quality impacts. 
Chapter 6 provides a brief overview of taxation and revenue issues associated with biodiesel. 
Chapter 7 looks at other issues that were raised in the literature review that may be of interest to 
the state. Finally, Chapter 8 summarizes the main findings of this report, and provides guidance 
for the phase 2 field test. 

Western Transportation Institute Page 1 

Evaluation of Biodie sel Fuel: Literature Review 

Background on Biodiesel 


Before proceeding to answer the research questions, it is important to establish some background 
about what biodiesel is, what it is made of, what its principal properties are, and the extent of its 
current usage in the state. This chapter will provide that foundation. 

2.1. Definition 

In 1895, Rudolf Diesel developed a new engine with the intention that it could use a variety of 
fuels, including vegetable oil. When he showcased it to the public at the 1900 Paris World's Fair, 
he had the engine run on peanut oil. As the diesel engine became more widely adopted in 
subsequent years, however, petroleum-based diesel fuel proved to be less expensive and became 
the fuel of choice (2). 

Biodiesel' s definition has been a work in progress. Since the early 1900s, biodiesel has been 
defined as an alternative form of diesel fuel made from vegetable oils or animal fats and alcohol 
(3). The definition of biodiesel was neither legally definable nor defensible in the United States 
for about a century. This changed when biodiesel was registered with the U.S. Environmental 
Protection Agency (EPA) as a fuel and a fuel additive under section 211(b) of the Clean Air Act 
(4). With help from the American Society of Testing & Materials (ASTM), subsequent 
legislation such as the Energy Policy Act (EPAct) helped further define biodiesel. In December 
2001, the ASTM issued defined physical/chemical constraints for biodiesel and subsequently for 
mixtures of biodiesel with diesel fuel (5). 

An important distinction needs to be made between bbdiesel and biodiesel blends. Biodiesel is 
commonly mixed with diesel No. 2 to form a biodiesel blend. As stated above, a mixture of 
biodiesel and diesel is not biodiesel, but is referred to as a biodiesel blend. Pure biodiesel, also 
known as neat biodiesel, is commonly noted as B100, indicating that the fuel has 100 percent 
biodiesel (noted by the 100) and percent diesel. The most common biodiesel blend is B20, 
which contains 20 percent biodiesel and 80 percent diesel. 

2.2. Manufacture 

Biodiesel is derived from biological sources, such as vegetable oils or fats, and alcohol (3, 6). 
Commonly used feedstocks are shown in Table 2-1. 

Table 2-1: Feedstocks Used for Biodiesel Manufacture 

Vegetable Oils 

Animal Fats 

Other Sources 

jeS Soybeans 

eS Lard 

jeS Recycled Restaurant 

jeS Rapeseed 

si Tallow 

Cooking Oil (a.k.a. 

jes Canola Oil (a modified version of rapeseed) 

jeS Poultry Fat 

Yellow Grease) 

jeS Safflower Oil 

eS Sunflower Seeds 

jeS Yellow Mustard Seed 

Western Transportation Institute 

Page 2 

Evaluation of Biodiesel Fuel: Literature Review Background on Biodiesel 

Most commercial biodiesel is made by a chemical process called transesterification. This 
involves mixing the feedstock oil with an alcohol - typically methanol or ethanol - in the 
presence of a catalyst, such as sodium hydroxide or potassium hydroxide. The reaction produces 
methyl esters (if methanol is used) or ethyl esters (if ethanol is used) - which comprises the 
biodiesel fuel - and glycerin (7). Methanol is typically used for economic reasons, as the 
physical and chemical properties between methyl esters and ethyl esters are, according to a 
University of Idaho study, "comparable" (8) 1 . 

Europe has been using biodiesel more extensively than the United States. Europe commonly uses 
rapeseed methyl ester. The predominant biodiesel used in the U.S. is soy methyl ester. 

2.3. U.S. Standards 

Biodiesel has been registered with EPA as a fuel and a fuel additive under section 211(b) of the 
Clean Air Act (4). Recently the definition of biodiesel was further sculpted through the ASTM 
standard for biodiesel, which may be added to conventional diesel fuels up to a B20 blend (5). 
This standard, issued in December 2001, is listed in Table 2-2. 

The existence of a national biodiesel standard limits the quantity of poor quality biodiesel 
available on the market, providing buyers with more consistent fuel performance, and 
encouraging producers to provide an appropriate product. This also provides a more favorable 
environment for adoption of pro-biodiesel legislation at the Federal and State levels. The 
standards can be met with a variety of feedstocks and manufacturing processes; therefore, the 
biodiesel market is currently based not on the feedstock used, but on the standards that are met. 
If buyers are interested in using a specific feedstock, they may have to adjust the fuel 
specifications slightly to meet their needs (9). Ignoring parts of the standard could impact engine 

2.4. Fuel Properties 

Biodiesel is made up of fourteen different types of fatty acids, which are transformed into fatty 
acid methyl esters (FAME) by transesterification. Different fractions of each type of FAME 
present in various feedstocks influence some properties of fuels. Table 2-3 shows some of the 
properties defined in the ASTM standards for diesel and biodiesel 2 . These properties are 
described in the remainder of this section, and will be referred to later in this report. 

According to the study, cloud and pour points were slightly lower for ethyl esters than methyl esters. However, 
ethyl esters showed slightly higher viscosity and slightly less power and torque (8). 

ASTM PS 121 was a provisional specification, superceded by ASTM D6751. The properties are understood to be 
the same. 

Western Transportation Institute Page 3 

Evaluation of Biodie sel Fuel: Literature Review 

Background on Biodiesel 

Table 2-2: ASTM Specifications (D6751) for B100 


ASTM Method 



Flash Point 


130 min. 


Water & Sediment 


0.050 max. 

% Volume 

Kinematic Viscosity (40 °C) 



mm 2 /sec 

Sulfated Ash 


0.020 max. 

% mass 



0.05 max. 

% mass 

Copper Strip Corrosion 


No. 3 max. 



47 min. 

Cloud Point 




Carbon Residue (100% Sample) 


0.050 max. 

% mass 

Acid Number 


0.80 max. 

Mg KOH/gm 

Free Glycerin 


0.020 max. 

% mass 

Total Glycerin 


0.240 max. 

% mass 

Phosphorous Content 


0.001 max. 

% mass 

Distillation Temperature, 
Atmospheric Equivalent 
Temperature (90% Recovered) 


360 max. 


The carbon residue shall be run on the 100% sample. 

Note: A considerable amount of experience exists in the U.S. with a 20 percent blend of biodiesel with 80 
percent diesel fuel (B20). Although biodiesel (B 100) can be used, blends of over 20 percent biodiesel with 
diesel fuel should be evaluated on a case-by-case basis until further experience is available. 

(Source: 10) 

Table 2-3: Comparison of Fuel Properties between Diesel and Biodiesel 

Fuel Property 



Fuel Standard 

ASTM D975 

ASTM PS 121 

Fuel composition 

C10-C21 HC 


Lower Heating Value, Btu/gal 



Kin. Viscosity, @ 40° C 



Specific Gravity kg/I @ 60° F 



Density, lb/gal @ 15° C 



Water, ppm by wt 


.05% max 

Carbon, wt % 



Hydrogen, wt % 



Oxygen, by dif. wt % 


Sulfur, wt % 

.05 max 

0.0 -0.0024 

Boilinq Point (°C) 

1 88-343 

1 82-338 

Flash Point (°C) 



Cloud Point (°C) 

-1 5 to 5 

-3 to 1 2 

Pour Point (°C) 

-35 to -1 5 

-1 5 to 1 

Cetane Number 



Stoichiometric Air/Fuel Ratio wt./wt. 



BOCLE Scuff, grams 



HFRR, microns 



(Source: JJ_) 

Western Transportation Institute 

Page 4 

Evaluation of Biodiesel Fuel: Literature Review Background on Biodiesel 

The lower heating value refers to the energy content, or energy per unit mass, of the fuel 
excluding the heat produced by evaporation of water vapor in the fuel (12). As can be seen, B100 
has lower energy content than diesel by eleven percent. This results from the higher oxygen 
content of the fuel that produces more complete combustion of the fuel and soot (11). B100 has 
higher kinetic viscosity than diesel, which improves injector efficiency. Biodiesel has a higher 
specific gravity and density (pounds per cubic foot) than conventional diesel No. 2. Since fuel 
flow is controlled by volume, the expected peak power reduction for engines using B100 is only 
5 to 7 percent less than conventional diesel No. 2 because more pounds per gallon would flow 
and vaporize more efficiently given a set throttle (volume) (13). It should be noted that biodiesel 
produces more than three times the energy as the same amount of fossil fuel (14). Biodiesel' s 
higher specific gravity and density relative to diesel No. 2 means that on- road biodiesel blends 
are normally made by splash blending the biodiesel fuel on top of the conventional diesel fuel 

By weight, biodiesel contains less carbon, sulfur and water and more oxygen than diesel. The 
reduced carbon content decreases tailpipe emissions of carbon monoxide (CO), carbon dioxide 
(CO2) and soot (elemental carbon). The lower sulfur content of biodiesel is important for two 
primary reasons. First, as a low sulfur fuel, biodiesel produces little or no emissions of sulfur 
dioxide (SO2). SO2 contributes to respiratory illness, aggravates existing heart and lung diseases, 
contributes to the formation of acid rain, can impair visibility, and can be transported over long 
distances (15). Second, EPA regulations will reduce the level of sulfur in highway diesel fuel by 
97 percent by mid-2006 (16). Biodiesel is already compliant with the 2006 standard (17). 
Biodiesel' s higher oxygen content allows it to burn more completely than conventional diesel, 
thereby reducing hydrocarbon and carbon monoxide emissions (18). 

Biodiesel and diesel have a common boiling point, but biodiesel has a higher flash point - the 
temperature at which a fuel will catch fire - because biodiesel has a high number of FAMEs 
which are generally not volatile. Thus, biodiesel is safer to handle at higher temperatures than 

Biodiesel is similar to diesel no. 2 in that both fuels need to be used cautiously in cold climates, 
as wax crystals can form in either fuel at lower temperatures. These wax crystals can plug fuel 
filters, causing engine stumbling or stalling. A variety of temperatures are used to reflect wax 
crystal formation, two of which - cloud point and pour point - are listed in Table 2-3. Cloud 
point is the temperature at which a haze or cloud of wax crystals first appears in the fuel when it 
is cooled under test conditions. Pour point is the lowest temperature at which diesel fuel will 
flow when cooled under test conditions (19). Both of these temperatures are related to the lowest 
temperature at which a diesel engine will be able to operate. As can be seen in Table 2-3, the 
pour point and cloud point are both higher for biodiesel fuel than for gasoline-based diesel, 
indicating that biodiesel will tend to gel at higher temperatures than diesel, causing engine 

Biodiesel' s effects on cloud point for soy methyl ester and rapeseed methyl ester biodiesel can be 
seen in Figure 2-1. Slight effects on cold weather performance emerge when biodiesel comprises 
20 percent or less of the fuel. It should be noted that there is some difference in cloud point based 
on feedstock used, with vegetable source biodiesel having the lowest cloud points, animal 
sources having the highest cloud point, and yellow grease falling in between the two (20). 

Western Transportation Institute Page 5 

Evaluation of Biodie sel Fuel: Literature Review 

Background on Biodiesel 

Percent Biodiesel (blended with diesel 2) 

-»— Soy 


(Source: 22) 

Figure 2-1: Cloud Point as Function of Increasing Biodiesel Percentage 

With respect to vehicle use, a more meaningful measurement that can be listed by the user in fuel 
specifications is the cold flow plug point (CFPP), or the temperature when fuel flow stops 
through an unheated 4- micron fuel filter mesh. The CFPP for diesel No. 2 is -31 °C compared to 
-10 to -14 °C for rapeseed methyl ester B100 (21). 

The Natbnal Biodiesel Board says that B20 blends can be used in cold weather environments in 
a similar manner as diesel No. 2, such as by using pour point depressants (especially malan- 
styrene esters [2JJ), blending with diesel No. 1, using engine block heaters, and storing vehicles 
in or near buildings (23). Adjusting the blend of kerosene in the diesel fuel can modify the cloud 
and pour point temperatures of B20 as well. Figure 2-2 shows the cloud and pour point when 
B20 is produced from diesel fuels. Four different biodiesel feedstocks are shown - two varieties 
from yellow grease and two from soy. B20 with D2 is a blend of 20 percent biodiesel with 80 
percent diesel No. 2. The other two B20 blends shown are blends of 20 percent biodiesel with 80 
percent winterized diesel fuel. In one case the winterized diesel consists of 80 percent diesel No. 
2 and 20 percent diesel No. 1 and in the other case the winterized diesel consists of 60 percent 
diesel No. 2 and 40 percent diesel No. 1. The cloud and pour points of the diesel No. 2, diesel 
No. 1, and the two winterized diesel fuels are also shown for comparison. This chart ultimately 
demonstrates that the cloud and pour points of B20 can be improved (lowered) by adjusting the 
amount of diesel No. 1 in the diesel fraction of the mix. Diesel No. 1 (kerosene) and pour point 
depressants, which work on the diesel part of a biodiesel blend and can reduce the gelling and 
clouding properties of blended fuels, have been used with good results in B20. No additives have 
been shown to be effective on B 100 (11) . 

Western Transportation Institute 

Page 6 

Evaluation of Biodie sel Fuel: Literature Review 

Background on Biodiesel 

Yellow Grease 1 

Yellow Grease 2 

Soy 1 

Soy 2 

Yellow Grease 1 

Yellow Grease 2 


Soy 2 

■ B100 DB20w/ Diesel 2 
□ B20w/ Winter 2 DDiesel2 
DWinter 2 (60% D2, 40% D1 ) DDiesel 1 

□ B20w/ Winter 1 

DWinter 1 (80% D2, 20% D1) 

(Source: 11) 

Figure 2-2: Cold Weather Properties of Biodiesel Fuels and Blends 

Western Transportation Institute 

Page 7 

Evaluation of Biodie sel Fuel: Literature Review 

Background on Biodiesel 

The cetane number is a measurement of how well a diesel fuel combusts. Cetane numbers 
measure the ignition of diesel, much like octane numbers measure the ignition of gasoline. These 
numbers represent the measure of a fuel's willingness to ignite. Biodiesel has a higher cetane 
number than that of diesel, largely because of its higher oxygen content (24). It is important to 
note that biodiesel' s cetane number can vary widely, based on differences in fatty acid 
composition of the feedstock oil and the saturation level of the fatty acids (25). 

Lubricity, an important characteristic of fuel, is an indication of the amount of wear or scarring 
that occurs between two metal parts as they come in contact with each other (26). Different from 
viscosity (reviewed in Section 3.4), which measures a liquid's resistance to shear forces, lubricity 
measures the extent to which a liquid diminishes friction. Two primary tests are used to measure 
lubricity: the Ball On Cylinder Lubricity Evaluator (BOCLE) and the high-frequency 
reciprocating rig (HFRR) test. A BOCLE test involves pressing a ball bearing against a rotating 
ring immersed in the diesel fuel. Weight is applied on the bearing until the diesel fuel fails, 
leaving a scuff mark on the rotating cylinder (27). The HFRR test consists of a ball that is placed 
on a flat surface and then rapidly vibrated back and forth with a stroke distance of one millimeter 
while 200 grams of weight is applied. The vibratory motion closely models engine vibration. 
After a given time, the flat spot that has been worn into the ball is measured (27, 28) . 

According to both BOCLE and HFRR tests, biodiesel shows greater lubricity than diesel, which 
is an important benefit. As EPA regulations have required changes in diesel fuel - through 
removal of sulfur and aromatic s - lubricity has often been removed from diesel fuel in the 
process (26). B2 is being marketed as a lubricity additive or injector cleaner for diesel in some 
parts of the country, at a price of $2-4 per quart (9). Even such a small amount of biodiesel can 
significantly enhance lubricity. According to a National Biodiesel Board review of tests 
conducted by Stanadyne Automotive Corporation, "most of the lubricity benefits of the biodiesel 

Table 2-4: Summary of Biodiesel Properties for Various Feedstocks 



Diesel No. 






Frying Oil 

Cetane Number 

40 -52 







Flash Point, °C 

60 -72 








IBP, °C 





T10, °C 





T50, °C 






T90, °C 






EP, °C 





SDecific Gravity 








Lower Heatina Value. MJ/ka 





Higher Heating Value, MJ/kg 








Cloud Point, °C 

-25 to -1 5 







Pour Point, °C 

-25 to 5 







Cold Filter Pluoaina Point. °C 

-20 to -1 




Viscosity at 40 °C. CS 








Iodine Number 






(Source: 29 cited in 30) 

Western Transportation Institute 

Page 8 

Evaluation of Biodiesel Fuel: Literature Review Background on Biodiesel 

were achieved by adding only 2% biodiesel to either number 1 or number 2 diesel." (26). 

Biodiesel properties can vary according to the feedstock used. As shown in Table 2-4, however, 
there is a greater difference between conventional diesel and biodiesel than between various 
types of biodiesel. 

2.5. Regional Experience 

Anecdotal evidence indicates that biodiesel usage is growing in Montana. This section discusses 
the Yellowstone National Park "Truck in the Park" project, as well as other regional users of 
biodiesel fuel. 

2.5.1. Yellowstone National Park 

The most significant test demonstration of biodiesel in the region has been Yellowstone National 
Park's "Truck in the Park" project. Started as a cooperative effort between the park and Montana 
Department of Natural Resources and Conservation (now Department of Environmental Quality 
[DEQ]) to look for ways to reduce the smell and smoke of diesel in the park, this pilot project 
used rapeseed ethyl ester biodiesel (B100) in a new 1995 %-ton 4X4 pickup truck donated by 
Dodge Truck to DEQ for use in the Park. No modifications were made to the engine or fuel 
delivery systems. The project was pursued in a two-phase approach. Phase 1 involved answering 
technical questions about biodiesel, including safety and operation differences, performance 
capabilities at high elevations and over a broad range of temperatures, changes in performance 
over 100,000 miles (including chassis dynamometer tests), information on costs and benefits, 
and information on benefits and drawbacks of using biodiesel in environmentally sensitive areas. 
Phase 2 (the second 100,000 miles) investigates additional questions on biodiesel, assessing 
tradeoffs, and identifying specific applications for biodiesel (31). 

A 1995 Dodge pickup truck with a 5.9-liter Cummins B engine was operated on rapeseed-based 
B100 for three years, with about 100,000 driving miles logged as of 1997. No modifications 
were made to the engine; however, because of concerns with refueling for emissions tests in 
California, a 300- gallon heated tank was added to the truck (32). 

As of May 1999, no fuel-related problems had been reported. Initially, the engine lubrication oil 
was changed and tested every 6,000 miles. The first lube oil sample showed high silica content, 
which the manufacturer attributed to the final engine preparation. The first cold weather lube oil 
sample reported a change in viscosity, indicating possible fuel dilution. However, the 
manufacturer recommended increasing the frequency of oil changes for this engine type in the 
winter (regardless of fuel used) to every 4,000 miles because of increased idling. After following 
this recommendation, fuel dilution was never again detected. Chassis dynamometer tests showed 
6 percent less power with biodiesel than diesel, although drivers reported feeling no difference 3 . 

Chris Sharp, Southwest Research Institute, at the Commercialization of Biodiesel: Environmental and Health 
Benefits Conference at Yellowstone National Park in May 1996, said operators will only see a difference between 
diesel and biodiesel at peak power requirements that are seldom used in most field applications. 

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Evaluation of Biodiesel Fuel: Literature Review Background on Biodiesel 

Chassis and engine dynamometer Federal Test Procedure (FTP) emissions testing at Los Angeles 
and San Antonio showed a reduction in air toxic and criteria pollutants (e.g. hydrocarbons, 
carbon monoxide and nitrogen oxides) and the catalytic converter was reported to operate more 
efficiently with biodiesel. Emissions performance did not degrade over time, and no new 
compounds were detected (31) . 

The park stored the biodiesel fuel at Mammoth Hot Springs in a 10,000-gallon, single-walled 
unheated, gravity- fed, above-ground tank. There were initial concerns over cold weather 
performance, but it was soon realized that the biodiesel fuel would flow from the unheated, 
gravity- flow tank at temperatures as low as -20 °F if the nozzle was first cleared of solidified 
biodiesel (31) . The tank was situated to face south, so fueling was often done at mid-day to take 
advantage of solar heating in reducing gelling problems. With that measure in place, no gelling 
problems were reported (33). No cold flow or other additives were used in the biodiesel to 
improve its thermal properties. The park took no unusual cold weather precautions with the 
biodiesel truck. In the first three winters of operation, the truck failed to start during cold weather 
once, when the temperature was -37 °F and the block heater had not been plugged in (31). 

Semiannual chassis dynamometer tests were conducted with no noticeable differences in 
performance, power or fuel economy relative to diesel. An engine teardown by a Cummins 
engineers in 1999 revealed a spot of rust on the lube oil- side tip of the oil filter housing. 
However, there were no carbon deposits and the cylinders were exceptionally clean - like new 
(32, 34). According to one project partner, the engine was rated by the manufacturer after the 
100,000 mile test as "good or better than if diesel had been used." (35). The fuel economy for the 
truck was 16.3 miles per gallon, about 1 mpg less than conventional diesel 4 ( 31) . 

While there were some areas of concern in the evaluation, the park considered the demonstration 
to be a success, to the point that their entire diesel vehicle fleet - approximately 300 vehicles - 
now uses B20 (33). The park's usage of biodiesel makes it one of the most significant users of 
biodiesel in the country. According to Howard Haines from the Montana Department of 
Environmental Quality, the greater Yellowstone area used about 10 percent of biodiesel (B100) 
sold nationally (35). The park has installed a 15,000- gallon underground tank at Gardiner, where 
a local distributor splash blends the B100 fuel into trucks carrying conventional diesel (or 
winterized diesel) for delivery of B20 into Park tanks. The size of the tank allows the park to 
achieve significant price advantages on biodiesel. At the outset of the Truck in the Park project, 
biodiesel fuel for the park cost about $3 per gallon; now the park can get the fuel for only 2 cents 
per gallon more than diesel (33). The park plans to seek additional ways to use biodiesel fuel. 
They now use it for off-road applications, including generators and boilers, and are seeking to 
offer biodiesel fuel for sale to park visitors in 2004. The park hopes to increase the richness of 
biodiesel blends so as to eventually become petroleum- free (33). 

At the conclusion of the project, fuel economy was 17.1 miles per gallon, after the heads were adjusted per 
manufacturer's regular specs after 100,000 miles. 

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Evaluation of Biodiesel Fuel: Literature Review Background on Biodiesel 

2.5.2. Glacier National Park 

Glacier National Park converted their vehicle fleet to B20 in October 2002. Their primary 
motivations were to reduce vehicular emissions and reliance on fossil fuels. They are using the 
fuel year-round on approximately 50 vehicles within the park, including dump trucks and 
transports. The primary challenge they have reported is the price of the fuel, which has 
fluctuated. They have received funding assistance from the U.S. Department of Energy to make 
the fuels more affordable. According to the park's facility manager, biodiesel is "here to stay" 

2.5.3. Grand Teton National Park 

Grand Teton National Park converted their entire fleet of diesel maintenance vehicles to 
biodiesel blends in June 2001. According to the park's fleet manager, the decision to use 
biodiesel was in response to a National Park Service mandate for parks to explore using 
alternative fuels. Biodiesel was perceived to be the best alternative fuel option in terms of fuel 
acquisition. The park uses B20 for eight months of the year, and B10 for four months with the 
base diesel being 50 percent diesel No. 1 and 40 percent diesel No. 2. They used this approach 
on blending in order to achieve a cold pour point of -25 to -28 °F. The park did this proactively - 
not in response to fuel gelling - to ensure that emergency response vehicles would have no 

The fleet manager reports that the park has not had any significant problems with using biodiesel 
blends. There has been some difficulty starting vehicles that are stored outside - most park 
vehicles are stored inside - but vehicles have been able to start with biodiesel blend. They had 
initial problems with the quality of fuel supplied, but have been more proactive in testing fuel 
quality and have had no problems since. The park is reporting better fuel economy with biodiesel 
blends. After conversion, there was an initial need to change fuel filters more frequently, but 
there are reported to be no additional maintenance costs at this point. Moreover, because it is a 
cleaner fuel, the fleet manager anticipates that long-term engine life will be better. The park has 
concluded that there is additional cost with biodiesel - 4 to 5 cents per gallon in the summer and 
1 1 to 12 cents per gallon in the winter 5 - but that it is cheaper than alternatives. The park has also 
received favorable press for using biodiesel. 

Grand Teton is investigating long-term incorporation of other alternative fuel options in addition 
to biodiesel and ethanol, including propane and compressed natural gas. Nevertheless, the fleet 
manager sees biodiesel playing a major role in fuel for park vehicles even with other alternative 
fuels entering the mix ( 37) . 

The additional cost is relative to the cost of conventional diesel (diesel No. 2 in summer, and winterized diesel in 

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Evaluation of Biodiesel Fuel: Literature Review Background on Biodiesel 

2.5.4. Other Regional Users 

Biodiesel is now being used at Malmstrom Air Force Base in Great Falls, where the base's entire 
diesel fleet has been converted to B20 (38). Fleet usage is also reported in Bozeman and at the 
Bureau of Land Management in Lewistown (9). 

At the time of publication, there is one Montana public fueling station that provides year-round 
biodiesel blend fuel. The station, in West Yellowstone, charges the same price for biodiesel as 
others charge for diesel. However, they change the blend rates varying between BIO and B20 
based on fuel cost and ambient temperature (9). 

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Evaluation of Biodiesel Fuel: Literature Review Engine Performance Characteristics 


One of the biggest concerns for any prospective biodiesel user is whether an engine using 
biodiesel will perform differently than an engine using normal gasoline-based diesel. This 
section of the report will assess previous studies' findings on engine performance effects of 
biodiesel in the following categories: torque and power, engine fatigue and damage, fuel 
economy, and viscosity. This chapter will also discuss issues related to engine warranties and 
studies of off- road use of biodiesel. 

Before exploring the results of various studies, a couple of considerations are in order. First, the 
introduction of a standard for biodiesel fuel has improved the quality of biodiesel and made its 
properties more consistent. Second, there have been changes in diesel fuel (reduced aromatic, 
benzene and sulfur content) lubricating oil specifications in the last few years. As newer research 
has incorporated these improved standards and specifications, some of the engine problems 
found in testing biodiesel fuel have been addressed. 

3.1. Torque and Power 

Performance of any fuel can be judged by the power and torque output that it can generate. 
Biodiesel has a higher cetane number than conventional diesel, but has a lower energy content 
per volume. Because of the lower energy content, using biodiesel without any change in the fuel 
injection system would result in a slight loss of engine power. Numerous studies have been 
undertaken to test these theoretical results. It should be noted that power and torque is difficult, if 
not impossible, to accurately measure in- use; therefore, power testing has occurred in controlled 
laboratory environments with specific duty cycles that are designed to stress engines. For 
example, the 200-hour Engine Manufacturers Association (EMA) test includes significant time 
where the tested engine is operating at full throttle ( 39) . 

However, the results of various studies have not been uniform. Studies indicate that the amount 
of power loss may be influenced by various factors, such as the engine make, overall 
maintenance of the vehicle, type of diesel used as base fuel, and condition of the air filter. B20 
users may or may not experience this loss of power, whereas people using B100 may feel a loss 
of power. Ziejewski et al. (40), Niehaus et al. (41) , Schumacher et al. (42), Reece and Peterson 
(43), and Marshall (44) observed power reductions ranging from one to seven percent. 
Schumacher observed a three percent increase in power using a 1991 Cummins 5.9L direct 
injection (DI) turbocharged engine. Increased power was also observed by Feldman and Peterson 
(45) during a 200 hour EMA test using a 3 cylinder, DI, naturally aspirated diesel engine with 
the injection timing advanced 2 degrees. Schumacher (46) detected very small differences in 
power until the fuel contained at least 50 percent biodiesel by volume. He also observed a steady 
drop in exhaust gas temperature for both the rated and peak torque condition, indicating a shift in 
the peak pressure point toward top dead center, resulting from an increasingly shorter ignition 
delay. The lower exhaust gas temperature was a result of increased heat transfer into the coolant. 

Results with B20: Schumacher (47) tested B20 with diesel No. 2 with a 20:80 ratio on Navistar 
engines and found a power change ranging from a 13 percent increase to a 3 percent decrease. It 
should be noted that most of these engine tests showed a slight decrease in power with B20 as 

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Evaluation of Biodiesel Fuel: Literature Review Engine Performance Characteristics 

compared to conventional diesel. The Iowa Department of Transportation (48) used B20 in nine 
snow removal trucks, four tractors, a motor- grader and a wheel- loader during a one- year 
demonstration in 1995 6 . A seven percent loss of power was observed when the snow removal 
trucks where filled with a combination of diesel No. 1 and biodiesel, whereas no loss of power 
was observed when the trucks were filled with diesel No. 2. 

Results with B100: Schumacher (49) filled a Cummins engine from a 1992 Dodge truck with 
B100 and found that there was a change in power ranging from a 6 percent increase to a 7.8 
percent decrease; the change of power depended on the engine design and fuel delivery. User 
trials have found a general loss of power ranging from 5 to 10 percent. 

Studies at the University of Idaho for Yellowstone National Park concluded that power output is 
reduced by about 6 percent when measured at the wheels (31) . Although studies have found that 
there is a reduction in power output ranging from 1 to 8 percent for B100, there is no overall 
marked difference in biodiesel blends between B20 and B50. User trials have shown that drivers 
generally do not perceive any loss of power. The loss of power may result from various reasons 
dependent on the make and model of engine and general vehicle maintenance. User trials have 
not shown any instances of vehicles failing midway or engines breaking down as a result of a 
biodiesel or biodiesel-blend fuel. There have been some instances of engines overheating, but 
there are no overall trends in that regard. 

3.2. Engine Durability and Materials Compatibility 

While engine durability testing of biodiesel blends is ongoing, most studies have shown no 
appreciable difference between biodiesel and conventional diesel fuel. A 1984 study conducted 
by Clark et al (50) found that engine wear rates for engines in 200, 500 and 1,000 hour tests were 
well within specified ranges. In one study conducted at the University of Missouri (49), a 1992 
Dodge pick-up truck with a Cummins engine was tested after approximately 100,000 miles of 
operation. After the miles were logged on the truck, the engine was disassembled and sent to a 
team of Cummins Engine Company experts. The report from Cummins engineers revealed a 
normal wearing rate of the engine. During the same study, Bosch diesel fuel injectors were 
analyzed by the manufacturer after 50,000 miles of operation with 100 percent biodiesel. They 
reported no problems with the injectors and approved the use of B 100 in their fuel systems. 

The lubricity benefits of biodiesel, especially compared to low- sulfur petroleum diesel, help to 
reduce engine wear. Research at the University of Saskatchewan since the early 1990s has 
indicated that the use of biodiesel contributes to a tenfold reduction in engine wear (51) . A 
research project at the University of Idaho focused on biodiesel made from used vegetable oil 
(hydrogenated soy ethyl ester or HySEE). Test vehicles included several trucks, newer tractors, 
and a Ken worth semi- tractor with a Caterpillar engine driven with 50 percent HySEE for 
200,000 on-the-road miles. These studies showed that various blends of biodiesel produced 

Iowa DOT reported some problems with B20. An instance of fuel gelling occurred on a truck that had an in-line 
heater and not an in-tank heater. Gasket deterioration was observed in a couple of locations. A high amount of 
particulate emissions was observed during start-up. Nevertheless, Iowa DOT concluded that there did not seem to be 
any major operational problem with B20. They discontinued the project for cost reasons (48). 

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Evaluation of Biodiesel Fuel: Literature Review Engine Performance Characteristics 

engine wear similar to, or less than, petroleum diesel and produced the same or better engine 
durability (52, 53). 

Some earlier studies showed fuel dilution as a result of using biodiesel (54^ 55, 56), while other 
studies, including more recent studies (Schumacher et al [57] and Schumacher and Madzura 
[58]) indicated that fuel dilution of engine oil was not a problem. Most earlier studies showing 
fuel dilution used a diesel fuel significantly different than current No. 2 specifications, and diesel 
engine technologies that are significantly different than the drier, tighter designs used on the road 
since 1996. The EMA has taken a conservative stand on this issue, recommending that when 
using biodiesel, the normal oil change interval should be cut by half to minimize problems 
associated with engine lubricating oil (59). 

There are some precautions that should be considered when utilizing biodiesel (60). Since 
biodiesel is a natural solvent and will soften and degrade certain types of elastomers and natural 
rubber compounds, precautions are necessary to ensure that engines manufactured before 1994 
do not have seals made of these types of elastomers. Due to the switch to low- sulfur diesel fuels 
in 1993, virtually all diesel original equipment manufacturers (OEMs) have pursued 
fluorocarbon (Viton) type seals, which do not experience problems with biodiesel. In general, 
problems with gaskets, hoses and seals are less pronounced as the percentage of biodiesel in the 
fuel decreases (61). 

3.3. Fuel Efficiency 

A study organized by Schumacher & Madzura (58) found that there was no significant difference 
in fuel economy between a normal diesel fuel and B20 fuel. Their observation was based on a 
study that monitored the fuel economies of five B 20- fueled buses and five buses fueled with 
conventional diesel in St. Louis. In another research project conducted at the University of 
Missouri (57), a 1991 and a 1992 Dodge pick-up truck were fueled with diesel until 3,000 miles 
and 1,500 miles of operations respectively, and then filled with soy diesel. Results indicate that 
fuel efficiency fluctuated depending on how the trucks were used. The overall efficiency of the 
1991 truck was 16.7 mpg and the 1992 truck was 16.6 mpg. The highway fuel efficiency of the 
trucks was 22.8 mpg for diesel fuel, but it was 22.3 mpg when operated on 100 percent soy 
diesel. It was concluded that fuel economy was the same for both types of fuel under same 
circumstances. In a similar kind of study (62), 100 percent soy diesel was used in a heavy-duty 
DDC 6V-92TA-coach engine provided by Fosseen Manufacturing and Development. Fuel 
consumption for both biodiesel and diesel on a mass basis was very similar for all blends tested. 
User trials in Yellowstone National Park (as described in sectbn 2.5.1) have also not found any 
differences in fuel economy (32). 

3.4. Viscosity 

Viscosity measures the resistance of a liquid to shear forces. Viscosity is another important 
property of biodiesel since it affects the operation of fuel injection equipment, particularly at low 
temperatures when the increase in viscosity affects the fluidity of the fuel. Biodiesel has higher 
viscosity than conventional diesel fuel. High viscosity leads to porer atomization of the fuel 
spray and less accurate operation of the fuel injectors. The viscosity of biodiesel and biodiesel 

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Evaluation of Biodiesel Fuel: Literature Review Engine Performance Characteristics 

blends also increases more rapidly than diesel as temperature is decreased. Certain impurities 
also tend to significantly increase the viscosity of biodiesel. 

According to Romano (63), in an experiment involving fueling a diesel engine with methyl ester, 
when metals such as tin, lead and cobalt come in contact with fatty acids at high temperatures, 
they react readily with these acids, thereby reducing the viscosity of fuel. He cautioned that after 
200 to 250 hours of operation, the diesel engine crankcase oil fueled with 100 percent vegetable 
oil methyl ester lost its lubrication properties. Hassett and Hasan (64) also expressed concerns 
about diluting lubricating oil. 

3.5. Warranties 

A critical issue regarding adoption of biodiesel blends is whether their use in on- road diesel 
engines would void warranties with engine manufacturers. Moreover, the warranty policies of 
engine manufacturers may shed light on the industry's assessment of the suitability of biodiesel 
for long-term use. Engine manufacturers do not cover damage caused by fuels - diesel, biodiesel, 
or otherwise. Fuel producers and/or distributors cover damage traceable to the products they sell. 

The general view of the EMA - the self- described "voice of the engine manufacturing industry 
on domestic and international public policy, regulatory, and technical issues that impact 
manufacturers of engines" (65) - is that biodiesel blends at less than five percent are generally 
acceptable, but higher blends need to be evaluated (13). Caterpillar (66), Cummins (67) and John 
Deere (68) all specifically allow B5 or lower biodiesel blends in their engines. Caterpillar allows 
pure biodiesel in some of its engines, including the 3046, 3064, 3066, 3114, 3116, 3126, 3176, 
3196, 3208, 3306, C-10, C-12, 3406, C-15, C-16, 3456, 3408, 3412, 3500 series, 3600 series, 
CM20, CM25 and CM32 engines (66). Detroit Diesel allows blends up to B20, although doesn't 
advise use of fuels above B5 (69). International had initially suggested a maximum blend of B5, 
but now permits a maximum of B20, to allow users to take alternative fuel credits (70) (see 
section 6.2.2). One of the problems faced by EMA ( 71) in certifying the use of biodiesel in 
engine warranties is that biodiesel suppliers must warrant their fuel quality that has to be used in 
the engines; therefore, OEMs require that the biodiesel fuel used in a biodiesel blend meet the 
ASTM standard. Many engine manufacturers, including Caterpillar |56), Cummins (67) and 
International (70) , indicate that the use of biodiesel fuel does not affect the engine material and 
workmanship warranties. Another problem for EMA is that the diesel fuel injection equipment 
manufacturers, Injection Equipment Manufacturers Association, only provides coverage for their 
products up to 5 percent of any additive until a certain amount of field data is evaluated (72). 

No engine manufacturers provide warranties to cover damage that may be attributed to the use of 
any fuel, including biodiesel blends. Engine manufacturers take responsibility for defects 
attributable to materials and workmanship; fuel producers and distributors are responsible for the 
fuel, whether it is biodiesel or conventional diesel. Engine manufacturers seem to agree that low 
biodiesel blends (less than B5) will not cause problems. Cummins states, "Given the current 
industry understanding of bio fuels and blending with quality diesel fuel, it would be expected 
that blending up to a 5% volume concentration should not cause serious problems." (67) 
Nevertheless, engine manufacturers do recommend some additional precautions, such as the 
following, when biodiesel is used (66, 67, 68) . 

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Evaluation of Biodiesel Fuel: Literature Review Engine Performance Characteristics 

?? Monitor the engine oil condition to determine the optimum oil change interval. 

?? Increase the frequency of fuel filter replacement in the early stages of conversion of 
an older engine to biodiesel use. 

?? Monitor the condition of seals and hoses (this reflects OEM concern over the long- 
term compatibility of Viton with biodiesel). 

?? At low ambient temperatures, consider the use of heated storage for fuel, and heated 
fuel lines, filters and tanks. 

?? Consider the usage of oxidation stability and anti- microbial additives. 

?? Monitor water content of fuel regularly, as it facilitates microbial growth and can 
create acids in bonding with the biodiesel. 

?? Keep storage and vehicle tanks as full as possible to prevent moisture from collecting 

Some engine manufacturers may permit richer biodiesel blends, but they may require additional 
specifications, such as iodine number, cold flow plug point number or a pour point specification 
on the biodiesel or biodiesel blend (9, 73). The Federal government and Department of Defense 
require additional specifications for diesel and biodiesel, including a cold flow plug point and the 
use of "virgin" vegetable oils (74). 

3.6. Off-road Vehicles 

The primary focus of this analysis has been to look at on- road vehicles. This section provides a 
brief examination of off-road vehicles, since they represent important users of diesel fuel in 

A study documented in a 1994 report monitored and recorded quantitative data related to fuel 
consumption, power, and exhaust emissions while fueling Case- International 5120, 5130 and 
5250 and Ford 4600 and 7740 tractors with blends ranging from to 100 percent biodiesel (75). 
Material compatibility problems were noted when fueling with an experimental biodiesel fueling 
station. The B100 dissolved the rubber fill hose after one month of use so that fuel leaked from 
the hose when refueling. John Deere tractor models 6300, 7200 and 7800 ran hotter when fueled 
with biodiesel. The tractors were tested for power while changing between blends of 0, 10, 20, 
30, 40, 50 and 100 percent biodiesel blended with diesel No. 2. Testing occurred on the same 
day, under similar temperature and humidity conditions, and within minutes of the previous test. 
When each engine was fueled with conventional diesel, the viscous fan that is designed to 
engage when cooling needs are the greatest, seldom engaged. The viscous fan almost always 
engaged when fueled with a biodiesel blend. The power that each engine was able to produce 
declined as the concentration of biodiesel increased. However, the decline in power seldom 
exceeded 1 to 3 percent except when the engine was converted to B100. 

Changes in lubricating oil and fuel specifications in recent years may make results of previous 
studies incomparable. The University of Idaho completed testing of off-road vehicles with 
rapeseed methyl ester. The Mitsubishi Satoh Tractor operated the first 650 hours on a fuel blend 

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Evaluation of Biodiesel Fuel: Literature Review Engine Performance Characteristics 

of 50 percent rapeseed methyl ester and 50 percent diesel No. 2 (56). Rubber fuel lines were 
replaced with Viton fuel lines, but no other changes were necessary to convert the tractor to 
methyl ester fuel. Routine maintenance included collecting engine oil analysis samples and 
changing the oil and filters for oil, fuel, and air every 100 hours. No problems attributable to the 
fuel were noted. Specifically, no fuel filter plugging or power loss was noted when fueling with 
methyl esters. In another study, a John Deere 3150 tractor operated for 50 hours with diesel No. 
2 and then with a B50 rapeseed methyl ester blend thereafter, and showed no detectable power 
loss. Rubber fuel lines were replaced with Viton fuel lines. Routine maintenance included engine 
oil analysis of the lubricating oil and replacement of fuel, air and oil filters every 100 hours. 
Smoke emissions (opacity) appear reduced when performing heavy tillage loads. 

Recent experience with B20 in off- road applications has been favorable. In the spring of 2001, 
the Missouri Department of Transportation (MoDOT) began using B20 in approximately 600 
diesel vehicles and pieces of diesel equipment, including motor graders, dump trucks, off- road 
vehicles, high lifts, pull-behind message boards, and other miscellaneous diesel powered 
equipment. A MoDOT mechanic supervisor noted that biodiesel has "excellent lubricating 
qualities" and "much better" emissions, and that the switch from diesel to B20 was "a transparent 
change." (76) The U.S. Department of Agriculture (USDA) issued a memorandum in August 
2001 requiring USDA agencies, such as the Forest Service, that maintain diesel fuel tanks for 
their fleet vehicles, off-road vehicles, marine vessels and other motorized diesel equipment to 
buy and use biodiesel in B20 or higher blends "where practicable and reasonable in cost." (77) 
Regional Forest Service users of B20 include the Bridger- Teton, Salmon-Challis, and Caribou- 
Targhee National Forests, where they have used B20 in about 100 off-road vehicles over the past 
year or so (53). 

A variety of tractor engines have warranties for biodiesel or biodiesel blends, as shown in Table 

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Evaluation of Biodiesel Fuel: Literature Review 

Engine Performance Characteristics 

Table 3-1: Summary of Warranties for Tractors, Since 1996 


Type of Vehicle 

Warranty Status 

Case IH 


all models since 1971 


combines, tractors 

warranties exist 

Faryman Diesel 


warranties exist 



for new models 

Ford AG 


for new models 



warranties exist 



series 3000 and 5000 

John Deere 

tractors, combines 

warranties since 1 987 



warranties exist 



series OC, Super Mini, 05, 03, 



serie 1000 



since 1989 



since 1988 



series M 16 TCAM and M 14 TCAM 



since 1991 

(Source: 78) 

Western Transportation Institute 

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Evaluation of Biodiesel Fuel: Literature Review Transportation, Handling, Storage 


For any new fuel to be widely accepted and used, its characteristics relative to ease of use should 
be comparable to existing fuels. The following chapter of the report addresses the transportation, 
handling and storage of biodiesel fuels. 

4.1. Transportation 

Since biodiesel gels at low temperatures, it is difficult to transport biodiesel like any other diesel 
fuels at low temperatures. Some of the methods recommended for transportation of biodiesel 
(11) are: 

?? Kept hot in tank cars for immediate delivery, 

?? in insulated rail tank cars equipped with steam coils (the tank cars are melted with 
steam at the final destination as needed), 

?? in 20 percent blends with available winter diesel, or 

?? in a 50 percent blend with diesel No. 1 (kerosene). A 50:50 blend of soy biodiesel and 
kerosene has a pour point of 0° F in most cases. 

4.2. Handling 

"Clean" B100 - made from methyl and ethyl esters of soy and other vegetable oils - is not 
corrosive to skin. However, blends of biodiesel can cause irritation and a burning sensation to 
sensitive body parts, so it is advisable to wear rubber gloves while dealing with biodiesel. 
Spontaneous combustion may be a problem because the fuel can oxidize in the air; consequently, 
rags that contain biodiesel and other combustible material should be put in closed metal cans or 
dried individually (7, 23). Biodiesel is also considered essentially nontoxic (11). 

4.3. Solvency 

Since biodiesel is a mild solvent, it may help to remove engine deposits that settle in the storage 
tanks of vehicles as well as systems. As a result, fuel filters in vehicles may become plugged, 
giving a false impression that biodiesel plugs filters, while it actually helps clear out sediments 
deposited in storage tanks. If biodiesel or a biodiesel blend is used in an engine where diesel No. 
2 was previously used, fuel filters will initially get clogged as the biodiesel cleans out deposits 
left by diesel No. 2. These problems are most pronounced in B100 in older (pre- 1992) engines; 
some problems have been observed with B20, and no problems have been reported with B2 ( 61) . 
It is recommended that one should read the guidelines provided for that kind of biodiesel before 
using higher biodiesel blends in their vehicles. 

As was mentioned in the last chapter, biodiesel can also act as a solvent for certain elastomers 
and natural rubber compounds, thereby affecting engine components like gaskets and seals as 
well as older fuel dispensing equipment. As is true with recent engine designs, fueling station 

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Evaluation of Biodiesel Fuel: Literature Review Transportation, Handling, Storage 

systems have started using materials that are compatible with biodiesel. One fuel dispenser 
manufacturer states that there should be ro problems with low-blend biodiesel blends (e.g. B5 7 ) 
(79). It should be noted that the Department of Defense has concluded that biodiesel is fully 
compatible with military specification diesel No. 2 (80). 

Biodiesel can act as a solvent on painted surfaces, so spills on painted surfaces should be wiped 
immediately (23). 

4.4. Biodegradability and Stability 

Biodiesel degrades about four times faster than conventional diesel (11): European tests of 
rapeseed-based biodiesel show that it is 99.6 percent biodegradable within 21 days ( 81) . 
Moreover, blending biodiesel with diesel fuel accelerates its biodegradability. For example, B20 
with a diesel No. 2 base degrades about twice as fast as diesel No. 2 alone (11). 

A possible downside to biodiesel' s high biodegradability is the potential for the fuel to have a 
shorter stability for storage. As biodiesel contains more polyunsaturates in its fuel compositio n 
than conventional diesel, it will have reduced stability (unless stability additives are used). 
Stability encompasses thermal stability under both hot and cold temperatures, resistance to 
oxidation, polymerization, water absorption, and microbial activity (30) . Instability in biodiesel 
is caused by the presence of unsaturated fatty acid chains. 

Oxidative stability test methods, currently under development, will allow customers to determine 
if the fuel will remain stable in storage over extended periods and to test fuels to determine if 
they have degraded during storage. ASTM D6751 does not contain any test methods for stability 
at this time. 

4.5. Storage 

Diesel fuels gel at lower temperatures; likewise biodiesel gels at lower temperatures. The main 
factor that defines the temperature at which any fuel gels is the presence of saturated components 
in that fuel. As the fuel gels, its flow properties are affected, inhibiting its ability to flow out of 
storage tanks and choking fuel filters and hoses. If any degraded fuel in a storage tank gets 
consumed by an engine, there is a potential for deposits and sludge in the fuel system. Biodiesel 
degrades four times faster than diesel and at the same rate as dextrose (a sugar). Hence, it 
becomes necessary to store fuel at proper temperatures and in stable environments. 

B100 can be stored at temperatures 15 degrees higher than the pour point of the fuel (30-50 °F). 
Temperatures of 45-50 °F are acceptable for most B100. Normally, diesel and biodiesel blends 
should be stored at 15 °F higher than the pour point of the blended fuel. 

For blends up to B20, the same manufacturer recommends potential replacement of fueling hoses, use of different 
paints, and some filtering (79). 

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Biodiesel's required storage temperature generally depends upon the storage environment. Like 
petroleum diesel, biodiesel should be stored in a clean, dry, dark environment. Extremes of 
temperature should be avoided when possible, since biodiesel has a higher cloud point and pour 
point than petroleum diesel. Acceptable materials for biodiesel storage include black mild steel 8 , 
stainless steel, fluorinated polyethylene, and fluorinated polypropylene. Concrete and concrete 
lined tanks should be avoided since biodiesel tends to degrade concrete over time (82). 

B100 can be stored underground in most climate conditions, but above ground fuel systems 
should be protected with insulation, agitation, heating system, or other measures. The 
requirements for above-ground storage of B20 are the same as for petroleum diesel. In the case 
of B100, it may be treated the same as the storage of vegetable oil. The biodiesel user should 
check with the local fire marshal and appropriate agencies to determine whether any special local 
regulations pertain to such storage. There are no special concerns at a state level: the Montana 
Department of Environmental Quality does not regulate the storage of biodiesel as it is not a 
hazardous substance. 

The requirements for underground storage of B20 or other biodiesel blends are regulated in 
accordance with EPA standards, and are the same as for petroleum diesel. Storage of B 100 is not 
regulated by EPA, but must be reported to the local fire marshal as with storage of vegetable oils 
and chemicals. Information concerning these regulations can be found in the Code of Federal 
Regulations 40 CFR 280. 9 

Regarding cold weather storage, user experience at Yellowstone National Park, which has an 
above ground storage facility 1 , showed fuel stratification at -20 °F. But the fuel flowed at even 
colder temperatures Q). B20 blends have been used in Wyoming and Minnesota where the 
temperature has fallen below -40° F (11). 

The U.S. Department of Energy (DOE) fact sheet on biodiesel reports that "in most cases" 
biodiesel can be stored as long as conventional diesel - up to six months (23). DOE did not 
recommend storage of biodiesel longer than six months without the use of fuel additives (83). 
Howard Haines from the Montana Department of Environmental Quality (DEQ) added that 
storage of biodiesel blend fuel could be a problem if the base diesel is dirty or has a high glycerol 
content. He noted that in Yellowstone's demonstration the same fuel was used for 28 months 
with the energy output and a viscosity within three percent of original levels (9). 

According to staff at the Montana Department of Environmental Quality, there is some evidence reported in work 
done at the University of Idaho that heated mild steel tanks may have problems for storing biodiesel, whereas 
ambient temperature mild steel tanks have no problem. 

Yellowstone National Park currently uses a 15,000-gallon underground storage tank for B100. The Montana 
Department of Environmental Quality reviewed the installation of the tank and determined that neither DEQ nor 
EPA regulate such activity. However, complete permitting and an inspection were conducted at installation, so that 
the tank could be converted for storage petroleum products in the future, if necessary. 

No permit was needed for the above ground tank, as it contained B 100. 

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This section of the report examines the differences between biodiesel and conventional diesel, 
with respect to emissions of hazardous airborne toxins. After a discussion of the types of 
emissions considered in this chapter, various studies are reviewed to summarize the effects of 
biodiesel on emissions, with air quality implications reviewed at the close of the chapter. 

5.1. Emission Types 

The scope of the emissions impact analysis of this report covers five types of emissions: NO x 
(nitrogen oxides), PM (particulate matter), HC (hydrocarbons), CO (carbon monoxide), and CO2 
(carbon dioxide). While CO2 is not a hazardous air toxin, it is considered a greenhouse gas 
emission causing global warming and, in some cases, may be capable of generating emissions 

5.1.1. NO x 

Nitrogen oxides (NO x ) is the generic term for a group of highly reactive gases containing 
nitrogen and oxygen in varying amounts, including nitric oxide (NO), nitrous oxide (N2O), 
nitrates (NO3"), and nitrogen dioxide (NO2). NO x and volatile organic compounds, in the 
presence of hot, stagnant air and sunlight, convert to ozone. 

NO x are classified as hazardous airborne toxins because of their deleterious health and 
environmental effects. The U.S. Environmental Protection Agency (EPA) has noted that NO x is a 
major cause of ground- level ozone (a.k.a. smog), acid rain, respiratory disease (emphysema and 
bronchitis), water quality determination, and global warming (84). 

5.1.2. PM 

Particulate matter (PM) is a generic term used for a type of airborne pollution which consists of 
varying mixtures, complexity and sizes of particles. PM is problematic because it compounds 
respiratory problems, such as asthma and cardiopulmonary disease (85). The American Lung 
Association reports that high concentrations and/or specific types of particles have been found to 
present a serious danger to human health (86). 

There are two types of regulated PM: PM2.5 and PM10. PM2.5 is a particulate matter of 2.5 
micrometers or less in diameter and PM10 is a particulate matter of 10 micrometers or less in 
diameter. Both PM2.5 and PM10 are byproducts of internal combustion engines (85). There are 
two major differences between PM2.5 and PM10. First, the size contributes to greater health risks 
because larger particles can be inhaled and accumulated in the respiratory system (87). Secondly, 
in contrast to PM2.5, PM10 easily reacts with chemicals such as SO2, NO x , and volatile organic 
compounds (VOCs). All of these chemical reactions can result in smog (85). 

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5.1.3. HC 

The Agency for Toxic Substances and Disease Registry reports that hydrocarbons (HC) "enter 
the air mostly as releases from volcanoes, forest fires, burning coal, and automobile exhaust" 
(88). A 1999 EPA study estimates that on-road vehicle sources were responsible for 29 percent 
of the total emission of HC (89). 

Mobile sources release two types of regulated HC measured as speciated hydrocarbons (C1-C22) 
and a subset of known or suspected carcinogenic compounds titled polycyclic aromatic 
hydrocarbons (PAH). A presentation given to the National Biodiesel Board entitled "Biodiesel 
Tier I Health Effects" presented a correlation between the emission rate of Q to C12 and the 
potential reduction of ozone and also stated that HC are a carcinogen (90). The Department of 
Health and Human Services reiterated this health concern, specifying that some PAHs are known 
to cause cancer (91). 

5.1.4. CO 

Carbon monoxide (CO) is produced from incomplete combustion whenever any carbon fuel, 
such as gas, oil, kerosene, wood, or charcoal is burned (92). Unlike many gases, CO has no odor, 
color, or taste, and it does not cause skin irritation. According to the Centers for Disease Control 
and Prevention red blood cells can attach themselves to CO at a quicker rate than oxygen. If 
there is a large quantity of CO in the air, the red blood cell may replace oxygen with CO, leading 
to possible tissue damage, carbon monoxide poisoning or death (93). As CO levels increase and 
remain above 70 parts per million (ppm), symptoms may become more noticeable (headache, 
fatigue, nausea). As CO levels increase above 150 to 200 ppm, disorientation, unconsciousness, 
and death are possible (94). 

5.1.5. C0 2 

Carbon dioxide is a naturally occurring gas that is linked to global warming. It is also released 
into the atmosphere by human activity, such as when solid waste, fossil fuels (oil, natural gas, 
and coal), and wood and wood products are burned (95). Carbon dioxide by itself is not 
considered to be a toxin. However, any impacts on global climate could cause health problems 

5.2. Review of Emissions Studies 

The EPA conducted a review of studies comparing the emissions of heavy-duty highway 
engines 1 ' using diesel No. 2 with similar vehicles using biodiesel (B100) or biodiesel blend fuels. 

The report focused on studies examining heavy-duty highway engines because of the lack of studies on heavy- 
duty highway engines reporting data taken using Federal test procedure (FTP) testing. Statistical correlations were 
developed for highway engines, and these were compared to those estimated through heavy-duty engine studies. The 
report concluded the following: "For PM and HC, the vehicle data appears to produce emission benefits that are 
smaller than those predicted by the [statistical] correlations. For NO x the vehicle data appears on average to produce 
emission reductions whereas the [statistical] correlations predict emission increases. For CO, the vehicle data 

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They conducted a regression analysis estimating the relative emissions change as a function of 
the percent of biodiesel used in the fuel blend. They conducted analyses for biodiesel based on 
the percent blend of biodiesel using different types of feedstock (soy, rapeseed and animal). This 
study documented the percentage for each type of biodiesel used (soy, rapeseed or animal-based) 
and its respective change, relative to diesel No. 2, of four types of emissions - NO x , PM, HC and 
CO. As this review encompassed nearly 40 studies, it is believed that it provides a 
comprehensive picture of the differences in emissions between biodiesel and diesel (96). 

Table 5-1 summarizes the change in levels of 
toxic emissions between diesel No. 2 and a soy- 
based B20 blend - a commonly used biodiesel 
blend. The following source impacts, for 
emission reductions due to soy-based biodiesel 
compared to diesel No. 2, are ranked from 
greatest to lowest: HC, CO, PM. These 
comparative benefits are chiefly related to 
biodiesel' s high oxygen and low sulfur content 
(24). Conversely, soy-based biodiesel NO x 
emissions increased slightly as compared to 
diesel No. 2. 

Table 5-1: Source Impacts on Using Soy- 
Based B20 Compared to Average Diesel 

Source Effect 

Percent Change 
in Emissions 

NO x 







-1 1 .0% 

(Source: 96) 

The report also examined whether there were statistically significant differences in emissions 
levels between biodiesel and diesel. They expressed the results of this analysis in terms of p- 
values. A p- value greater than 0.05 illustrates that there is no statistically discernable difference 
at a 95 percent confidence interval. The p-values in Table 5-2 show that emissions levels are 
significantly different between biodiesel and diesel No. 2 for all four pollutants. They also show 
that there is a significant difference between biodiesel types for NO x , PM and CO emissions. 
There was no significant difference in HC emissions between biodiesel types (animal fat, 
rapeseed and soy). These results are described in more detail for each pollutant in the sections 

Table 5-2: P- Values for Biodiesel Source Effects 





Do Source Effects... 









Change with % biodiesel? 









Animal x % biodiesel 









Rape x % biodiesel 









Soy x % biodiesel 









(Source: 96) 

appears to produce larger emission benefits than the [statistical] correlation predictions. Based on this comparison, 
we do not believe that the vehicle data can be used to represent the emission effects of biodiesel on heavy-duty 
diesel engines." (96 ) Vehicles carrying a greater load will produce more vehicle emissions; however, there are no 
indications that the emissions impacts of biodiesel change as vehicle load increases. 

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5.2.1. NO x 

As seen in Table 5-1, soy-based B20 emits 2.0 percent more NO x than diesel No. 2. According to 
the EPA study, the biodiesel types are significantly different from one another. As seen in Figure 
5-1, each type of biodiesel showed higher emissions of NO x than diesel No. 2. Soy-based 
biodiesel showed the most significant increase in NO x emissions, animal-based biodiesel the 
smallest, and rapeseed showed an increase between the two ( 96) . 



75 15 



% 10 




1 5 




40 60 

Percent biodiesel 



(Source: 96) 

Figure 5-1: Biodiesel Source Effects of NO x 

The increase in NO x is partially rooted in biodiesel' s higher cetane number. Dr. Kerr Walker 
from the Scottish Agricultural College reports that higher NO x emissions result primarily from 
the shorter ignition delay time of biodiesel 12 (97). The piston of the engine moves due to 
advancement of a hot flame front that results from the ignition of the air- fuel mixture. The 
typical air- to- fuel mixture for a diesel engine is 7 parts of air to 10 parts of fuel. As air contains 
80 percent nitrogen, most of the air- fuel mixture is nitrogen. NO x is created when an 
oxygen/nitrogen mixture is subjected to high temperatures and pressures. At the start of 
combustion, the combustion chamber on a diesel engine is filled with air. The oxygen and 
nitrogen mixture is under high pressure and is fairly hot. If there is a delay in the ignition timing, 

" According to staff from the Montana Department of Environmental Quality, recent studies suggest that NO x 
emissions are related to engine technology and injection pressure: slow and medium-speed (medium-pressure) diesel 
engines show no or little increase in NO x , while engines with high injector pressure (~300 psi) show slight rises in 
NOx (53). 

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a large amount of accumulated fuel suddenly ignites, creating a very hot flame front, and 
probably creating a large amount of NO x (98). 

This problem can be remedied by changing the engine timing. Steve Howell of the Society of 
Automotive Engineers reported that research indicates retarding engine timing to lengthen 
ignition time can mitigate increases in NO x emissions from biodiesel (99). This statement is 
echoed by Dr. Walker: "Adjustment of injection timing and engine operating temperature will 
result in these levels [of nitrogen oxides with biodiesel] being reduced below mineral diesel 
levels." (97) 

Although the mean engine timing has the potential of matching the cetane number, there still lies 
the problem of biodiesel' s cetane rating varying more than diesel. According to the EPA study, 
biodiesel has a "widely varying natural cetane" relative to diesel 13 (96). Therefore, regardless of 
engine timing modification, biodiesel is statistically expected to emit more NO x than diesel due 
to its greater cetane level variance. It's important to note that cetane numbers in association with 
engine timing are a significant factor in NO x emissions, but not the only factor. The National 
Biodiesel Board notes that, because of biodiesel' s lack of sulfur, a variety of NO x control 
technologies may be applied that would not be applicable with conventional diesel (100) . 
Examples of these technologies include NO x adsorbers and lean NO x catalysts, which have 
demonstrated the potential to control greater than 50 percent of diesel engine NO x emissions 
(101) 14 . 

There are other strategies that may be used to reduce NO x in biodiesel blends 15 . Lowering the 
aromatic content in the base fuel, or using diesel No. 1 (kerosene) as a base fuel, can both be 
effective. Cetane enhancers di- tert-butyl peroxide (DTBP) and ethyl- hexyl nitrate (EHN) may 
also be helpful ( 102 ). Another option is to blend biodiesel using different feedstocks. It has been 
reported that iodine numbers in animal-based biodiesel are lower than those for soy- or rapeseed- 
based biodiesel, so it has been suggested by Thornton that blending high iodine number fuels and 
low iodine number fuels could help mitigate the increase in NO x ( 103 ). Exhaust gas recirculation 
has also been shown to reduce NO x of B20 by 10 percent, in comparison with the results 
obtained through altering injection pressure and optimizing engine timing ( 104 ). 

Both conventional diesel and biodiesel can be blended to achieve a certain cetane. Cetane number is not typically 
included as a specification for biodiesel, although it has been added as a specification by some users (for example, 
the military). 

The Manufacturers of Emission Controls Association (MECA) adds the lower sulfur fuel can lead to adoption of 
control technologies to impact HC and PM emissions as well, such as commercially available PM and HC filters that 
use a NO x catalyst to help destroy diesel particulate emissions. MECA adds that lower sulfur fuel "further enhances 
the performance of other PM and HC control technologies, such as oxidation catalysts and catalyzed diesel 
particulate filters, which can operate on current diesel fuels." ( 101 ) 

According to staff from the Montana Department of Environmental Quality, chassis dynamometer testing 
conducted at lower temperatures (~35° F) showed that less NO x was produced at lower operating temperatures. 
Therefore, the actual NO x impact of biodiesel in Montana may be less than indicated by the EPA analysis (53). 

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5.2.2. PM 

According to the EPA study, B20 soy-based biodiesel produces 10.1 percent fewer PM 
emissions than diesel No. 2 (96). Further, the percentage of PM being emitted decreases as the 
percentage of biodiesel increases, as seen in Figure 5-2. It should be noted that there was no 
significant difference between soybean and rapeseed-based biodiesel PM emission, but both 
exhibited a greater PM emission than that of animal-based biodiesel. 







Soybean or rapeseed-based biodiesel 


40 60 

Percent biodiesel 



(Source: 96) 

Figure 5-2: Biodiesel Source Effects of PM 

There is a tradeoff in diesel engine technology between producing fewer PM emissions (as seen 
in Figure 5-2), while creating more NO x emissions (as seen in Figure 5-1), since these emissions 
can react with other agents to form smog. The tradeoff of PM and NO x emissions may or may 
not be a problem. First, Alfuso found that rapeseed methyl ester oil reduced smoke levels in 
direct injected diesel engines (105 ). Figure 5-1, Figure 5-2, and Figure 5-3 show that soy, 
rapeseed and animal-based biodiesel blends have similar emissions attributes to that of the 
rapeseed methyl ester used in Alfuso' s experiment; it is likely that that there will also be a 
reduction in smoke. More specifically, it is possible that the tradeoff of PM and NO x for soy, 
rapeseed and animal-based biodiesel blends are tilted in favor of less smog. Secondly, NO x is a 
precursor to ground- level ozone formation. This process needs heat: in Montana, the 
temperatures are cool enough and there is a summer wind to prevent significant NO s formation 
(9). Therefore, given Montana's seasonal characteristics, it's unlikely for the potential of haze 
forming in Montana if smog is a factor. 

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5.2.3. HC 

Biodiesel has noteworthy benefits in reducing HC emissions relative to diesel No. 2. As seen in 
Table 5-1, soy-based B20 emits 21.1 percent fewer HC than diesel No. 2. The EPA report shows 
that there is no significant difference in the percent reduction of HC emissions between different 
feedstock types (rapeseed, soy and animal-based) (96) . 

5.2.4. CO 

As shown in Table 5-1, B20 (soy-based) biodiesel produces 11.0 percent less CO than No. 2 
diesel fuel. This trend is similar to biodiesel base types (soy, rapeseed and animal), as seen in 
Figure 5-3. The EPA report indicates that CO emission reductions vary according to the 
feedstock used 16 . As seen in Figure 5-3, the following biodiesel bases are in order of decreasing 
percent reduction of CO per percent biodiesel: animal, rapeseed then soybean-based biodiesel 

40 60 

Percenl biodiesel 


(Source: 96) 

Figure 5-3: Biodiesel Source Effects of CO 



Regarding carbon dioxide, the EPA report was not able to identify a clear difference between 
biodiesel and diesel. It noted that carbon dioxide benefits are attributed to biodiesel because of its 
nature as a renewable resource; however, the report did not quantify those benefits (96). 

An analysis by the University of Idaho shows that CO and other emissions vary by iodine number, which 
represents the amount of unsaturated carbon bonds. High oleic vegetable oils have the lowest CO emissions, lower 
PM emissions, relatively little impact on NO x emissions, and are the most stable (53). 

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A Department of Energy fact sheet on biodiesel did seek to quantify these benefits. It noted that 
plants that are used to make biodiesel draw CO2 from the atmosphere and recycle it back as the 
plants decompose. Because of the renewable nature of biodiesel, DOE estimated that methyl 
ester biodiesel produces 78 percent less CO2 than diesel (14, 83) . 

5.3. State and Regional Emissions Impacts 

Widespread adoption of biodiesel fuel within Montana may potentially have air quality impacts 
on a state or regional level. This section will examine the context for understanding the broader 
emissions impacts associated with biodiesel usage. 

5.3.1. Background 

In order to understand the potential air quality impacts of biodiesel, it is necessary to clarify 
some of the key regulatory agencies and legislation that govern air quality in Montana. 


The U.S. Environmental Protection Agency (EPA) was established in 1970 in response to a 
growing public demand for cleaner water, air, and land. The EPA develops and enforces 
regulations that implement environmental laws passed by Congress, offering financial assistance, 
performing environmental research, sponsoring voluntary partnerships and programs, and 
furthering environmental education. According to its Internet site, the agency researches and 
establishes "national standards for a variety of environmental programs, and delegates to states 
and tribes the responsibility for issuing permits and for monitoring and enforcing compliance. 
Where national standards are not met, EPA can issue sanctions and take other steps to assist the 
states and tribes in reaching the desired levels of environmental quality." ( 106) 

Clean Air Act 

The 1970 Clean Air Act (CAA) was the first piece of Congressional legislation to address air 
pollution on a national scale. It provides the primary framework for protection of air quality from 
all pollution sources, including stationary and mobile sources (16). 

CAA was significantly amended in 1977 and 1990. The 1977 amendments included establishing 
a national goal for visibility as "the prevention of any future, and the remedying of any existing, 
impairment of visibility in mandatory Class I Federal areas 17 where impairment results from 
manmade air pollution." The 1990 amendments provided additional emphasis on regional 
visibility, requiring EPA to work with several western states to address visibility in Class I areas 
in the Colorado Plateau. This led to the formation of the Grand Canyon Visibility Transport 
Commission (GCVTC) in 1991 (107 ). GCVTC issued its recommendations for dealing with 
visibility pollution in June 1996 ( 108) . 

Class I Federal areas are defined by CAA as national parks over 6,000 acres, wilderness areas over 5,000 acres, 
national memorial parks over 5,000 acres, and international parks that were in existence as of August 1977. 

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CAA requires each state to develop a state implementation plan (SIP) that explains how it will do 
its job in meeting the requirements of CAA. The SIP is a collection of regulations that a state 
will use to fulfill CAA and other environmental regulations. The SIP includes estimates of 
emissions from all sources, including stationary sources (e.g. heavy industry, power plants) and 
mobile sources (e.g. vehicles). 


The Clean Air Act, which was last amended in 1990, requires EPA to set National Ambient Air 
Quality Standards (NAAQS) for certain pollutants. The Clean Air Act established two types of 
national air quality standards: primary standards, which are aimed at protecting public health, 
and secondary standards, which protect the public welfare. EPA set NAAQS for the six principal 
pollutants shown in Table 5-3. It should be noted that the NAAQS only includes one nitrogen 
oxide compound - nitrogen dioxide (NO2). Nitrogen dioxide is a highly reactive gas formed in 
the ambient air through the oxidation of nitric oxide (NO). 

Table 5-3: National Ambient Air Quality Standards 


Standard Value 

Standard Type 

Primary Secondary 

Carbon Monoxide (CO) 

8-hour Average 
1-hour Average 

9 ppm 
35 ppm 


Nitrogen Dioxide (N0 2 ) 

Annual Arithmetic Mean 

0.053 ppm 



Ozone (0 3 ) 

1-hour Average 
8-hour Average 

0.12 ppm 
0.08 ppm 



Lead (Pb) 

Quarterly Average 

1 .5 ug/rrT 



Particulate (PM 10) 

Particles with diameters of 10 micrometers or less 

Annual Arithmetic Mean 
24-hour Average 

50 ug/m J 
1 50 ug/m c 



Particulate (PM 2.5) Particles with diameters of 2.5 micrometers or less 

Annual Arithmetic Mean 
24-hour Average 

15 ug/m 
65 uq/m 3 



Sulfur Dioxide (S0 2 ) 

Annual Arithmetic Mean 
24-hour Average 
3-hour Average 

0.030 ppm 
0.14 ppm 
0.50 ppm 




(Source: 109 ) 

While EPA has overall authority for enforcing environmental regulations, it delegates substantial 
authority to agencies in each state. In Montana, the Board of Environmental Review adopts 
regulations administered and enforced by the Department of Environmental Quality (DEQ). The 

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state has responsibility for submitting a SIP to EPA for its approval and for enforcing the 
regulations and control plans in the SIP. 

DEQ is responsible for a statewide ambient air monitoring network. NAAQS attainment is 
determined on an intrastate geographic basis depending on the nature of the pollutant and the 
extent of the concentration exceeding the NAAQS. For example, certain ozone precursors and 
PM2.5 tend to be regional in scope while ground-level ozone 18 , PM10 and CO, tends to be more 
localized. DEQ is responsible for monitoring air quality levels and defining the boundaries of 
attainment or non- attainment areas ( 110 ). 

Regional Haze Rule 

In 1999, EPA adopted a regional haze rule to address visibility impairment on a regional basis 
( 111) . All fifty states are covered under the regional haze rule. The rule relates to fine particles 
that are transported across state boundaries and includes specific provisions - 40 CFR 51.309 
(also known as "section 309") - for the nine states covered by GCVTC, which does not include 
Montana but does include two neighboring states (Idaho and Wyoming). Montana is subject to 
40 CFR 51.308 (section 308) which is more flexible in allowing states to implement what they 
believe to be the most effective measures for reducing their contributions to regional haze. 
Montana is only required to examine mobile sources if they are believed to be significant 
contributors to regional haze. Mobile sources are not a significant contributor to regional haze in 
Montana. According to Trista Glazier from DEQ, analysis by the Western Regional Air 
Partnership has indicated that regional haze reduction benefits from mobile sources are not as 
significant as originally believed. This reflects the usage of cleaner fuels over time and the 
continuing turnover of more efficient vehicles into the fleet (112) . After the natural background 
levels are established, Montana will focus its compliance efforts on emissions from various 
sources (including smoke management, prescribed burning and industrial sources) that cause or 
contribute to visibility impairment ( 112) . 

Section 308 states need to develop a state implementation plan by 2007 that will deal with SO2 , 
NO x and PM emissions. Section 309 states are allowed to focus on SO2 in their 2008 SIP, and 
will address NO s emissions afterward ( 113 ). 


The Western Regional Air Partnership (WRAP) is a consortium of 12 western states including 
Montana and 12 Native American tribes (including the Northern Cheyenne Tribe and the 
Confederated Tribes of Salish and Kootenai in Montana) who have partnered to deal with issues 
related to the Regional Haze Rule. WRAP is a collaborative effort of these governments and 
various federal agencies to implement the GCVTC s recommendations and to develop the 
technical and policy tools needed by western states and tribes to comply with the regional haze 
rule (114). 

According to staff from Montana DEQ, Montana does not have any ozone non-attainment areas, and DEQ does 
not currently monitor for ozone (53). 

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The primary role of WRAP is to provide modeling and technical expertise for member states in 
conducting air quality analyses to assist them in developing SIPs and emissions control 
strategies. Its current focus is primarily on section 309 states because these states have a more 
stringent timeline for demonstrating reasonable progress on visibility. WRAP will complete 
modeling and analytical work for section 308 states like Montana as well. WRAP has no 
statutory or regulatory authority, but is an important collaborative forum for dealing with 
regional air quality issues ( 112) . 

According to the Wyoming Department of Environmental Quality's emissions inventory 
coordinator, all states within WRAP - regardless of whether they follow section 308 or 309 - are 
presented with similar regional strategies as a result of WRAP's analysis. Each state can choose 
strategies based on what is most appropriate for their needs (113) . 

5.3.2. Potential Positive Impacts 

As was indicated in section 5.2, EPA studies indicate that biodiesel produces fewer emissions of 
several pollutants, including CO, PM and SO2, that are regulated by the NAAQS. Some potential 
impacts are discussed below. 

Reallocation of Emissions in SIP Budget 

A decrease in mobile source emissions of these pollutants could provide room in the state's 
emission budget to pursue less stringent emissions control strategies on stationary sources. To 
take advantage of this, the state would need to quantify the emissions reductions resulting from 
biodiesel. Therefore, WRAP would need to develop estimates of revised mobile source 
emissions with a significant biodiesel component; a significant reduction could affect air quality 
compliance strategies. Such reallocation must be approved by both DEQ and EPA. 

Emissions Credit Trading 

Another way to take advantage of reductions in mobile source emissions might be through the 
use of emissions credit trading. To this date, emissions trading has not been established for 
mobile source pollutants such as HC, CO and PM in Montana ror nationally. There is currently 
no emissions credit trading program for section 308 states (9, 112 ). 

Emissions trading has been used for SO2 , a major contributor to acid rain, in the Northeast. This 
concept imposed caps on SO2 emission levels on the dirtiest power plants in the Northeast. Plant 
owners that would find it costly to cut SO2 emissions can buy allowances from utilities that find 
it less costly. The program resulted in emissions reductions that were quicker than required at a 
cost level below forecast (115) . The Chicago Climate Exchange, which had its first auction in 
September 2003, is one organization that has formed to help develop similar markets for 
greenhouse gases, including CO2 . 

Several Montana companies recently formed a group called the National Carbon Offset Coalition 
(NCOC). NCOC intends to help landowners, corporations and government agencies participate 
in a market-based conservation program that can help to offset the environmental impacts of 
greenhouse gases, like CO2 . Example projects include conversion of pastureland to forested land. 

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Evaluation of Biodiesel Fuel: Literature Review Emissions and Air Quality Impacts 

The carbon sequestration benefits of a given project - how much CO2 is removed from the 
atmosphere - would be measured by long-term increases in the amount of carbon in soil. NCOC 
has produced initial guidance in assisting landowners who are interested in developing projects. 
One key element in the documentation is the discussion of "additionality," which essentially 
refers to the net carbon sequestration benefits of a given project. It takes into account what would 
have happened with a given piece of land under normal conditions and what the landowner 
decided to do to take advantage of credits for carbon sequestration ( 116 ). 

If land were put into active production of crops that could be used for biodiesel feedstocks, 
farmers could conceivably claim some carbon sequestration benefit. Theoretically, this could 
provide additional revenue to farmers, thus helping to offset some of the higher costs associated 
with producing biodiesel fuel (see section 7.1). The guidance indicates, however, that the critical 
question for assessing a carbon sequestration benefit is what the use of the land would otherwise 
have been. If a farmer converts one crop to another (for example, winter wheat to canola), it may 
not have any carbon sequestration benefit at all. 

Another possible benefit of biodiesel related to emissions trading is whether a large-scale 
producer of pollutants could financially benefit by producing fewer emissions. For example, a 
trucking company with a large fleet of vehicles that converts to biodiesel could show a reduction 
in emissions based on using biodiesel. They might be able to then sell these credits to another 
emissions producer (such as a factory). This could reduce emissions compliance costs for the 
factory, and could help the trucking company to offset the additional cost of fuel. The Chicago 
Climate Exchange does permit emissions from smaller sources (including vehicles) to be 
considered, although the focus is on electric power plants, and fossil fuel combustion and process 
emissions associated with the manufacturing sector. Mobile source emissions would need to be 
quantified using the Greenhouse Gas (GHG) Protocol, developed by the World Resource 
Institute/World Business Council for Sustainable Development, or other protocols developed by 
the Chicago Climate Exchange in order to be included (117 ). The GHG protocol standard 
includes mobile source emissions as part of a company's overall emissions production (118) ; 
however, no calculation tools are currently available to estimate emissions impacts of changing 
vehicle fuels or other aspects of a company's transportation infrastructure ( 119 ). Without 
approved calculation tools, it is unlikely that a firm could take credit for emissions reduction 
gained by switching to a biodiesel blend. 

Because of increased concern over greenhouse gases and the success of market-based 
approaches, emissions trading for carbon dioxide could occur in the future. This could provide a 
potential economic benefit with broader implementation of biodiesel fuel. Given the lack of a 
legislative mandate and the infancy of the emissions trading market, however, it is probably not 
prudent to count this as a significant advantage to using biodiesel at this time. 

Net Clean Air Benefits 

The state may choose to simply reduce mobile emissions in the state, which may help with 
conformity for areas in non- attainment (such as Billings, Great Falls, and Missoula). For parts of 
the state that are in attainment, the use of biodiesel allows for even cleaner air than required by 
Federal standards. 

Western Transportation Institute Page 34 

Evaluation of Biodiesel Fuel: Literature Review Emissions and Air Quality Impacts 

In considering this, it is important to put the net emissions reduction in context. For example, 
Missoula has a mobile source budget for PM-10. Of that budget, less than 2 percent comes from 
tailpipe emissions; the remainder is from re-entrained road dust (110) . (Dust can be dealt with 
through reductions in vehicle miles of travel [VMT] and/or paving of roads; in other words, it is 
independent of fuels used.) 

5.3.3. Potential Negative Impacts 

Section 5.2 indicated that, apart from altering engine timing and using fuel emulsions, biodiesel 
may lead to higher emissions of NO x per diesel vehicle. Potential negative impacts are described 
as follows. 


Although NO2 is a pollutant regulated under CAA, increases in NO2 are not likely to cause 
Montana to fall into non- attainment for NO2. One favorable element for Montana is that ground - 
level ozone formation requires heat and Montana's air tends to cool at night better than other 
parts of the country (such as the Los Angeles basin) (110 ). Moreover, ozone formation in the 
west tends to be limited by hydrocarbon availability, not NO x ; therefore, increased NO x 
emissions will not increase ozone formation without a significant increase in HC emissions 

Regional Effects 

One concern with increased NO x is how it would influence regional frameworks, such as WRAP. 
First, Montana - like all states outside of California - must use fuels and vehicle engines that 
comply with national standards. Biodiesel and biodiesel blends have been approved by EPA as 
acceptable fuels for on-road engines and approved diesel engines may use biodiesel as well as 
diesel. All WRAP analyses reflect these standards. 

Second, section 309 states are not required to address NO x mobile source emissions in their SIP 
until 2008. According to an environmental agency staff person in one section 309 state, 
biodiesel' s contribution to NO x could be an item of discussion at that time. However, given 
biodiesel' s minimal effect on NO x emissions - an estimated 2 percent increase for a B20 blend 
would be far smaller with a B2 blend - he indicated that such an effect would be insignificant 
from a regional perspective ( 113 ). 

Third, evidence indicates that increases in NO x emissions may be addressed through 
improvements in engine timing, which would render this question moot. 

Random Roadside Testing 

Some Western states, including Arizona and Nevada, conduct random roadside emissions testing 
of commercial ^ehicles. To date, this testing has focused on opacity only - the percentage of 
light blocked by exhaust - with a sliding scale used based on the age of the engine (120 , 121) . 
Some communities in Montana also have opacity laws (53). Since opacity is a measure of smoke 
(or visible PM emissions), it would not include NO x emissions ( 122) ; consequently, this should 

Western Transportation Institute Page 35 

Evaluation of Biodiesel Fuel: Literature Review Emissions and Air Quality Impacts 

be of no concern to vehicles using biodiesel. Moreover, studies have indicated that biodiesel 
decreases opacity: a 40 percent reduction using a B30 blend (123) and a 15 to 58 percent 
decrease using a B20 blend according to the University of Missouri ( 124 ). 

California has done experimental testing with in- use NO x measurement. The primary concern of 
their testing appears to be related to identifying engines in need of repair. Initial testing has 
indicated that engine repairs have resulted in minimal NO x reduction, and that there is no clear 
cut-off between low NO x - and high NO x -producing vehicles. Further testing is still underway 

Given the state of current roadside testing programs and the minimal adverse NO x impacts of 
biodiesel, it appears to be unlikely that heavy-duty vehicles would face fines in other states for 
using a B2 to B20 biodiesel blend. 

Western Transportation Institute Page 36 

Evaluation of Biodiesel Fuel: Literature Review Legislation 


Increased utilization of biodiesel could have a wide range of impacts on the national economy. 
For the agricultural sector, biodiesel would provide a new market for their products. As biodiesel 
fuel may cost more than conventional diesel, there could also be adverse economic impacts if 
costs are passed on in a variety of consumer goods. Those economic impacts are beyond the 
scope of this report. More pertinent to the thrust of this paper are the ramifications of increased 
biodiesel usage with respect to taxation, legislation and motor fuel tax revenues. These concerns 
are addressed at the Federal and State levels in this chapter. 

6.1. Europe 

Due to legislation between the years of 1992 and 1994, the European Parliament helped increase 
the production capacity of biodiesel to over 1.1 million tons per year. The increase in crop 
production and the resulting increase in biodiesel production are partially attributable to 
incentives created by two legislative factors. First, the Reform of the Common Agricultural 
Policy in 1992 helped biodiesel obtain a higher potential for market entrance. The reform added 
substantial subsidies for non-food crop production. The amount of land used to grow oilseeds for 
industrial purposes is estimated to have increased by 50 percent (about 0.9 million hectares) from 
1995 to 1996. Secondly, a tax break for non- imported (non- petroleum) fuels was instituted in 
February 1994; this was another major step for biodiesel' s entrance into the marketplace. Prior to 
this legislation, 50 percent of the pump price of diesel in Europe was due to taxes. The 
legislation created a 90 percent tax exemption for biodiesel, which provided monetary incentives 
for customers to use biodiesel over its counterpart, petroleum diesel ( 126 ). 

6.2. Federal 

6.2.1. Motor Fuel Tax 

The Federal government currently taxes diesel fuel at 24.4 cents per gallon. This taxation rate 
applies to diesel, biodiesel and biodiesel blend fuels equally. Some alternative fuels - liquefied 
propane gas, for example - have different tax structures, but these have not been applied to 
biodiesel yet. Interest in Federal tax incentives to promote biodiesel has led to discussion 
regarding reducing the motor fuel tax on diesel by one percent for every percent biodiesel blend 
used, up to B20 (9). However, no tax reductions have been applied to date. 

As a side note, if it is accepted that biodiesel offers less energy per unit volume than diesel, the 
current tax structure would mean that increased use of biodiesel would have a positive effect on 
Federal fuel tax revenues from diesel, since more gallons would be required to go the same 
distance. If relatively weak biodiesel blends (e.g. B2) are used, however, the positive effect 
would likely be trivial. 

Western Transportation Institute Page 37 

Evaluation of Biodiesel Fuel: Literature Review Legislation 

6.2.2. EPAct 

Congress passed the Energy Policy Act (EPAct) in 1992. The primary objective of EPAct was to 
reduce U.S. reliance on foreign oil by the promotion of alternative fuels. EPAct accomplishes 
this by giving tax breaks for supplying alternative fuels, such as biodiesel. This allows a higher 
priced biodiesel to more easily compete with diesel on the open market. The EPAct milestone in 
2000 was for "alternative fuels to represent 75 percent of all affected vehicle purchases for 
government fleets and 90 percent of all affected vehicle purchases by companies that 
manufacture alternative fuels." (30 ) The long-range goal of EPAct is a 30 percent reduction in 
imported petroleum by the year 2010 (30). Sections 501 and 507 of EPAct were designed to 
promote the use of non-petroleum fuels, such as ethanol, methanol, natural gas, propane, 
hydrogen, electricity and biodiesel ( 127 ). Subsequently, in October 1997, the definition of 
alternative fuels was expanded from biodiesel (B100) to any gradient between B100 and B20 
( 128) . This is important from a policy perspective because it provides additional incentive for 
fleets to invest in biodiesel. Although these are the current definitions, future additions to the 
alternative fuel list can be made though the Alternative Fuel Petition Program Section 301(2) of 
EPAct (128). 

EPAct encompasses the following three alternative fuel vehicle (AFV) credit programs: (1) State 
and Alternative Fuel Provider Program, (2) Federal Fleet Program, and (3) Private and Local 
Government Fleet Program. Due to community population requirements, however, all but a few 
Montana fleets are exempt from EPAct compliance and enforcement. 

?? The State and Alternative Fuel Provider Program requires certain fleets to acquire a 
given percentage (75 percent for state fleets and 90 percent for alternative fuel 
providers) of alternative fuel vehicles (AFVs) (30). Compliance is required by state 
government and alternative fuel provider fleets that operate, lease, or control 50 or 
more light-duty vehicles (LDVs) within the United States (20 of which need to be in a 
Metropolitan Statistical Area [MSA] and/or Consolidated Metropolitan Statistical 
Area [CMSA], neither of which are located in Montana). "Fleets that are subject to 
AFV acquisition requirements may comply by acquiring new or used AFVs, 
purchasing credits from other covered fleets, or using credits they have earned." ( 129 ) 
For every 450 gallons of B100 (2,250 gallons B20) purchased and consumed, a full 
vehicle credit is awarded (130 ). "They may also purchase certain biodiesel fuel 
blends or acquire conventionally fueled vehicles and have them converted within four 
months of purchase." (129) The Alternative Fuel Vehicle Credit Program allows 
covered fleets to buy and sell AFV credits and tax credits through the EPA website. 

?? The EPAct Federal Fleet Program is a legislative requirement for AFVs by Federal 
agencies. Starting in fiscal year 2000, this program required that alternative fuel 
vehicles "represent 75 percent of all affected vehicle purchases for government 
fleets." 6_0) Further, 2005 Federal fleets are required to reduce their petroleum 
consumption by 20 percent. EPAct set forth the statutory requirements for the 
acquisition of AFVs by Federal agencies ( 131) . All EPAct Federal Fleets must be in 
the MSA and/or the CMSA areas, neither of which are located in Montana. 

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Evaluation of Biodiesel Fuel: Literature Review Legislation 

?? The Private & Local Government Fleet Program is a program where the "EPAct 
gives DOE the authority to develop a vehicle acquisition program for private and 
local government fleets. However, before it can implement a private and local 
government fleet rule, DOE must first determine that a rule is necessary to achieve 
EPAct' s petroleum replacement fuel goals and that it is technically and economically 
practical. DOE is continuing to evaluate whether to implement a rule." (132 ) The 
following criteria must be met: 

o The company or local government owns, operates, leases or otherwise controls 50 
or more LDVs within the United States; 

o At least 20 of those LDVs are used primarily within a MSA/CMSA; 

o Those same 20 LDVs are centrally fueled or capable of being centrally fueled. 
LDVs are considered centrally fueled if they are capable of being refueled at least 
75 percent of the time at a location that is owned, operated, or controlled by any 
fleet, or under contract with that fleet for refueling purposes; and 

o Vehicles in the Private and Local Government Fleet Program cannot also be in the 
State program or the Federal program described earlier. 

For individuals or small businesses other than trucking, the purchase of large quantities of 
biodiesel doesn't seem to be a cost-effective solution. It is likely that this incentive, the tax 
break, will be passed on to the customer based on the comparatively high price of biodiesel to 
biodiesel' s competitor, diesel, and the assumption that the biodiesel distributor wants to stay in 

It should be noted that one of EPAct' s intents is to diversify the fuels used in transportation in 
the U.S. Therefore, an additional stipulation is that fleets may only substitute their biodiesel fuel 
consumption for up to one half of their total annual alternative fueled vehicle fuel purchase 
requirements ( 130) . 

6.3. State Legislation 

Several states have been considering biodiesel legislation in recent years, primarily out of a 
motivation to provide additional markets for local agriculture producers. A study by the Food 
and Agricultural Policy Research Institute (FAPRI) estimated that a demand for 70 million 
gallons of soy biodiesel could add from $0.10 to $0.18 per bushel to the price of soybeans ( 133) . 
The USDA Economic Research Service (USDA-ERS) estimated that if demand is 100 million 
gallons per year, then the price of soybean oil would increase by 14 percent ( 133) . The following 
are some examples of this legislation. 

Western Transportation Institute Page 39 

Evaluation of Biodiesel Fuel: Literature Review Legislation 

6.3.1. Minnesota 

Minnesota passed major biodiesel legislation in 2002, which requires 2 percent by volume 
biodiesel in diesel fuel sold in the state. One interesting component of this legislation is that it 
has contingencies that affect when the B2 requirement is in effect. A first contingency is that the 
mandate will be in force only after the state's agriculture commissioner certifies that the state has 
the capacity to produce 8 million gallons of biodiesel per year. The second contingency is that 
the mandate will not take effect until eighteen months after there is a two cent reduction in 
Federal taxes on biodiesel blend fuels, or June 30, 2005, whichever comes first ( 134 ). 

The Minnesota Soybean Growers Association used the economic analyses conducted by USDA- 
ERS and FAPRI to speculate that the Minnesota legislation would add 1.7 to 4.2 cents per bushel 
to the price of soybeans in the U.S. and 6 to 8 cents per bushel for Minnesota farmers, based on 
their favorable location. This would result in an estimated $4 million and $11 million in gross 
farm income, respectively, in Minnesota and would decrease federal outlays under the soybean 
marketing loan program in similar amounts ( 133) . 

6.3.2. Illinois 

Illinois Bill SB 46, which gave tax exemptions to biodiesel and ethanol fuel sold in the state, was 
signed into law in 2003. The law exempted biodiesel blends exceeding B10 from state sales taxes 
and reduced taxes by 20 percent on biodiesel blends between Bl and B10 (135 ). The state 
estimated that the exemptions would boost production of soybeans to 30 million bushels per 
year, adding $22.5 million to the Illinois economy. This was predicated on an assumption that 
the price of soybean bushels would increase by $0.05 (136 ). Illinois forecasts that they will 
increase the annual U.S. production of soybeans, about 3.0 billion bushels, by 30 million bushels 

It should be noted that the Illinois Bill SB 46 has secondary effects that may not have been 
adequately considered. First, SB 46 is likely to increase the marginal benefit of producing 
soybeans. This may result in more people producing soybeans and less production of other 
agricultural goods, such as corn. This shift in the marketplace, from corn to soybeans, has been 
going on since 2001 ( 138) and SB 46 is expected to continue this shift. In other words, Illinois 
may not end up increasing their economy by $22.5 million, but rather, marginally increasing 
their economy by artificially creating incentives for shifts in agriculture markets. Secondly, it 
should be noted that the alternative cost of SB 46 is less sales tax revenue going into state coffers 
to fund other government programs. 

6.3.3. Missouri 

In 2002, Missouri passed a law creating a biodiesel producer incentive fund with a $0.30 per 
gallon incentive on 15 million gallons per year for the first five years after the law takes effect. 
The funding for this incentive was to be provided by Proposition B, which would have increased 
fuel taxes in the state to generate nearly $500 million per year, primarily for transportation 
projects ( 139) . More than 72 percent of Missouri voters rejected the measure ( 140) , preventing 
implementation of the fund. 

Western Transportation Institute Page 40 

Evaluation of Biodiesel Fuel: Literature Review Legislation 

6.3.4. North Dakota 

Legislation in 2003 provided tax credits for retrofitting facilities to produce biodiesel. Other 
legislation, which would have mandated 2 percent biodiesel in all diesel sold in the state by 
2007, was defeated ( 141) . 

6.3.5. South Dakota 

Legislation mandating 2 percent biodiesel content in diesel fuel was considered in the state 
during 2002, but failed ( 142) . Legislation that would have reduced fuel taxes on biodiesel blends 
by two cents per gallon was also defeated (141 ). 

6.3.6. Hawaii 

Legislation effective as of January 1, 2002 reduced motor fuel taxes on alternative fuels as a 
proportion of diesel fuel taxes; biodiesel was charged at 50 percent of the diesel rate, with an 
additional 1 cent per gallon added ( 143 ). 

6.4. Montana 

Montana Code Annotated (MCA) 15-70-301 essentially defines biodiesel as a B20 blend ( 144) . 
Currently, according to MCA 15-70-370, the fuel tax is reduced by 15 percent for all biodiesel or 
ethanol fuel sold in the state ( 145 , 146) , an incentive which is in effect four years after an ethanol 
plant begins operation in Montana ( 147 ). It should be noted that the B2 blend, which was being 
proposed in the legislation considered by the Montana House, would not be included in this tax 
reduction. Montana currently taxes diesel fuel at 27.75 cents per gallon ( 148 ). In addition to the 
temporary tax reduction on biodiesel and ethanol fuels, motor fuel tax revenues are currently 
reduced by production incentives to encourage the use of Montana agricultural products to 
produce alcohol that could be mixed into motor fuels ( 149) . 

Western Transportation Institute Page 41 

Evaluation of Biodiesel Fuel: Literature Review Other Factors 


Research for this literature review identified a couple of additional factors that could affect 
policy decisions regarding biodiesel implementation in the state: cost and production 

7.1. Cost 

Perhaps the most significant reason that biodiesel has not gained wider acceptance in the U.S. is 
the cost of biodiesel relative to conventional diesel. Favorable taxation in Europe has allowed 
biodiesel to achieve approximate cost parity with conventional diesel. It is important to 
emphasize, however, that fuel taxes make fuel in European substantially more expensive than 
fuel in the United States. 

When looking at the cost of biodiesel production, most of the cost is from the feedstock used. 
Carnigal estimated that 91.52 percent of the production cost of biodiesel is the cost of feedstock, 
with operating cost and capital cost representing 3.12 percent and 5.34 percent of the production 
cost, respectively (cited in 150 ). Figure 7-1 (see page 43) compares estimated prices of canola- 
based biodiesel versus diesel from January 1995 to June 2003. The cost estimate for canola- 
based biodiesel assumes that 7.7 pounds of canola oil are required to make 1 gallon of biodiesel, 
with processing costs ranging from $0.15 to $0.50 per pound. As can be seen, the cost of 
biodiesel is generally much higher than diesel. Biodiesel blends, however, may be relatively 
competitive. Over the time period shown in the graph, B2 would cost 2.5 cents more per gallon 
than conventional diesel, while B5 and B20 would have premiums of 6.2 cents and 24.9 cents 
per gallon, respectively, as compared to conventional diesel. 

The cost of biodiesel may be reduced by using alternative feedstocks. For example, current 
prices of canola and soybean oil are approximately 20 to 22 cents per pound. Prices per pound 
are lower for inedible tallow (14 cents), mustard oil (10 cents), yellow grease (9 cents), and 
brown or trap grease 19 (5 cents or cheaper) ( 151 , 152 ). In terms of oilseeds, it should be noted 
that different oilseeds have different oil content. Soybeans, for example, have about 20 percent 
oil content, while other oilseeds have as much as 50 percent. Rapeseed, the primary feedstock 
used for biodiesel in Europe, is about 40 percent (81). 

Lower quality feedstocks may help as well. While fuel quality does not appear to be affected, 
there are concerns that pour point could be increased. Moreover, a higher free fatty acid content 
may make processing more expensive (30). 

Few studies have examined life cycle costs associated with biodiesel as compared with 
conventional diesel. A 1994 study from the University of Georgia compared the costs of 
operating an urban bus for conventional diesel versus biodiesel and other alternative fuels. The 
report determined that while biodiesel was the lowest cost alternative fuel option for an urban 

Brown grease has significantly more free fatty acids than yellow grease, and therefore would not be suitable for 
use as a standalone feedstock in biodiesel ( 152 ). 

Western Transportation Institute Page 42 

Evaluation of Biodiesel Fuel: Literature Review 

Other Factors 





Apr-97 Jan-i 




Jan-01 Oct-01 Jul-02 Apr-03 

•Base Diesel 

•Biodiesel - Low 

•Biodiesel - High 

B2 -— B5 — *^B20 

(Sources: Canola Prices from 154 , 155 ; Biodiesel Price Methodology from 156 ; Diesel 
Prices from 157 , adjusted for 52.15 cents per gallon combined Federal and State tax) 

Figure 7-1: Price Comparison of Diesel Fuel vs. Canola Biodiesel Blends 

:>us, it was still more expensive than diesel. The authors concluded that the economics o 
biodiesel (and other alternative fuels) require "compelling environmental or socioeconomic 
benefits ... to warrant incentives for promoting alternative fuels." ( 153) 

From a biodiesel production standpoint, a 1998 University of Missouri-Columbia study indicated 
that between soybeans, sunflower, canola and animal fats, canola would be the lowest cost 
feedstock for production. However, because of the value of its co-products (e.g. meal), soybeans 
would result in a lower cost of productbn for biodiesel than canola (158) . This may be one 
reason why soybean oil continues to dominate the U.S. market as feedstock for biodiesel. 

Another consideration beyond the cost of production is the cost of transportation. The price point 
for shipping is dependent on sales volume, so larger volumes of biodiesel freight are less 
expensive to ship. Rates for shipping are currently estimated at $0.34/gallon for shipment by 
truck and $0.12-0.17/gallon for shipment by tank cars (9). Shipping costs would decrease as a 
biodiesel industry develops in Montana to meet local demand. 

7.2. Production Capacity 

In 2001, the National Biodiesel Board estimated the dedicated production capacity for biodiesel 
at 60 to 80 million gallons per year (159 ). Actual production, according to biodiesel producer 
applications to the U.S. Department of Agriculture's Commodity Credit Corporation bioenergy 

Western Transportation Institute 

Page 43 

Evaluation of Biodiesel Fuel: Literature Review Other Factors 

program, was about 35 million gallons in 2001, with most of that coming from soybeans ( 160) . 
Fuel- grade mono-alkyl esters can also be produced by the oleochemical industry, where there is 
an estimated excess capacity sufficient to produce 200 million gallons of biodiesel per year. The 
Board reported that production capacity could increase fairly quickly (159 ). About half of this 
capacity is designed for soybean oil, half for recycled restaurant cooking oil; both commodities 
are currently in surplus, so prices are not resource-constrained (161) . In a study that examined 
the availability of various feedstocks for biodiesel, it was concluded that "current and future raw 
material availability far exceeds current and future predicted demand based on the expected price 
uncompetitiveness of biodiesel versus diesel." ( 162 ) 

For comparison, the Federal Highway Administration reports that approximately 200 million 
gallons of diesel fuel were sold in Montana for motor vehicles in 2001, out of a national market 
of 30.2 billion gallons of fuel ( 163) . 

Western Transportation Institute Page 44 

Evaluation of Biodiesel Fuel: Literature Review Summary and Conclusions 


The purpose of this report has been to review current literature regarding the use of biodiesel in 
on- road vehicle applications. This chapter will summarize the main findings of the literature 
review, and outline recommendations for the phase 2 field test. 

8.1. Summary of Findings 

This section looks at some of the key findings of this literature review. 

?? In general, engine performance has not appeared to suffer significantly because of the 
introduction of biodiesel. There may, however, be some peak power loss and some 
increase in fuel viscosity. 

?? Recent studies have shown no significant wear concerns with biodiesel, especially 
when biodiesel is blended with good quality petroleum diesel. Material compatibility 
with seals and gaskets may be a concern on B100 or in older engines. 

?? One engine concern arises when an engine alternates between different fuel types. 
Conventional diesel leaves deposits in engines that biodiesel, as a solvent, will clean 
out. This can mean additional costs for replacing fuel filters initially, but these 
additional costs are not sustained over time. Moreover, this is less of an issue if a low 
biodiesel blend (B20 or less) is used or if biodiesel is used as an additive (B2). 

?? Cold weather product storage for low (less than B20) biodiesel blends should not be a 
problem. Biodiesel blends are already used on a widespread basis in several cold 
weather locations, including Yellowstone National Park, Glacier National Park, 
Grand Teton National Park and Malmstrom Air Force Base. Moreover, biodiesel has 
been approved by the EPA as a fuel additive (B2 or less). At least one public fueling 
station in Montana blends biodiesel into its conventional diesel. 

?? Numerous emissions studies have been conducted, and ably summarized by EPA. 
Most tests have been completed with B20 biodiesel blends. Biodiesel blends show 
emissions benefits for SO2, CO, CO2, HC and PM. Biodiesel blends show increased 
NO s emissions, which may be partly or fully mitigated by changing engine timing. 

?? There appear to be no significant motor fuel tax revenue implications from increasing 
the use of biodiesel in Montana. 

?? A significant barrier to broader implementation of biodiesel is its price. This is a 
difficult issue to resolve at this time since much of the cost of biodiesel is attributable 
to the feedstock and transportation, and not to production. Given a higher price, it 
would be important to consider how biodiesel might be superior to diesel. Biodiesel' s 
primary benefits are increased lubricity, domestic production, and reduced emissions. 

Western Transportation Institute Page 45 

Evaluation of Biodiesel Fuel: Literature Review Summary and Conclusions 

Only some instances have shown that biodiesel has significant performance 
advantages compared to conventional diesel. 

8.2. Recommendations for Phase 2 Testing 

Based on the findings of this literature review, many of the technical questions regarding 
biodiesel have been answered. Given increased utilization of biodiesel in cold-weather 
environments, and favorable reports regarding engine performance and maintenance, there seems 
to be a broad consensus that biodiesel is a safe and reliable fuel that can be used in limited 
quantities in biodiesel blends with minimal or no additional accommodation. 

The broader questions affecting future biodiesel policy in Montana would appear to be related to 
blend rate, user acceptance and cost. Therefore, the proposed field test of B20 blend in MDT 
maintenance vehicles in Havre and Missoula should provide an important screening for user 
acceptance of the fuel. There is significant cold weather experience with biodiesel and biodiesel 
has been used in winter roadway maintenance activities as well. Combining these factors in a 
field test in Montana would lend more credence to the ability of biodiesel fuels to succeed on a 
long-term basis in the state. 

Most research projects that have examined biodiesel performance have involved expensive 
testing procedures, such as chassis and engine dynamometers to test emissions and performance 
and engine teardowns by manufacturers' engineers. For example, the Yellowstone "Truck- in- the - 
Park" demonstration cost close to $500,000 with much of these costs from partners and grants 
(including the State of Wyoming) involving emissions and performance tests and fuel analyses 
(35). The results of these tests are conclusive enough that it would be inadvisable for MDT to re- 
do these tests in their own field test. The field test should focus on fuel economy, which can be 
easily measured, along with anecdotal evidence regarding fuel transportation, handling and 
storage, and engine maintenance. Operator and maintenance staff surveys will be important to 
gauge overall user acceptance. 

Perhaps a more critical question regarding the future of biodiesel in the state is the additional 
cost associated with using biodiesel blend fuels. Apart from changes in motor fuel tax policy on 
biodiesel at either a Federal or a State level or significant production levels, biodiesel blends will 
be more expensive than diesel. Some fuel vendors may choose to absorb the increased costs, as 
in West Yellowstone, but this would not be necessary if B2 is required for all diesel sold in the 
state. More detailed analysis regarding the economic impacts of biodiesel - positive impacts for 
farmers in general and Montana farmers in particular and negative impacts in terms of increased 
fuel prices that are directly or indirectly absorbed by consumers - would be essential when 
considering long-term policy regarding biodiesel. 

Western Transportation Institute Page 46 

Evaluation of Biodiesel Fuel: Literature Review References 


1. Letter from Rep. Karl Waitschies, Chairman of Montana House Transportation 
Committee, to Dave Gait, Director of Montana Department of Transportation, March 26, 

2. "Clean Alternative Fuels - Biodiesel," Environmental Protection Agency Fact Sheet, 
Document No. EPA420-F-00-032, March 2002. 

3. "Granite State Clean Cities Coalition - Fuel Types," Granite State Clean Cities Coalition 
Web Site, http://www.granitestatecleancities.Org/fueltypes.htm#biodiesel , Accessed on 
September 19, 2003. 

4. "Did You Know: Use of Biodiesel Fuel on International School Bus," International Truck 
and Engine Corporation Web Site, , Accessed on October 3, 2003. 

5. "Standards and Warranties," National Biodiesel Board Web Page, 
Accessed on November 3, 2003. 

6. "Clean Air Program: Summary Assessment of the Safety, Health, Environmental and 
System Risks of Alternative Fuel". USDOT. . 

7. Murphy, Michael J., H. Norman Ketola and Phani K. Raj, Summary and Assessment of 
the Safety, Health, Environmental and System Risks of Alternative Fuels, U.S. 
Department of Transportation, Federal Transit Administration, Report No. FT A- MA- 90- 
7007-95-1, March 1995. 

8. "Production and Testing of Ethyl and Methyl Esters," University of Idaho, December 
1994. Accessed at 
on October 30, 2003. 

9. Telephone conversation with Howard Haines, Montana Department of Environmental 
Quality, August 28, 2003. 

10. National Biodiesel Board, "Specification for Biodiesel (B100)," December 2001. 

11. Tyson, K. Shaine, "Biodiesel Handling and Use Guidelines," Report No. NREL/TP-580- 
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12. "Alternatives to Traditional Transportation Fuels 1999 - Table 12, Estimated 
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13. Engine Manufacturers Association, "Technical Statement on the Use of Biodiesel Fuels 
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14. Sheehan, John, Vince Camobreco, James Duffield, Michael Graboski, and Housein 
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17. National Biodiesel Board, "Biodiesel 2002: Indications that the Biodiesel Industry is 
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21. Huang, Chor and David Wilson, "Improving the Cold Flow Properties of Biodiesel," 
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Journal of the American Oil Chemists Society, Vol. 72, No. 8, 1995, pp. 895-904. Cited 
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30. Prakash, Chandra B., A Critical Review of Biodiesel as a Transportation Fuel in Canada. 
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31. Evanoff, Jim and John Sacklin, "Yellowstone National Park Evaluates Renewable, 
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34. Racosky, Joe, David Krutsinger, Saundra Dowling and Kevin Chandler, Federal Lands 
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37. Telephone conversation with Vic Lindeburg, Shop Foreman and Fleet Manager, Grand 
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47. Schumacher, Leon G., Steven C. Borgelt, Mark D. Russell and William G. Hires, 
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48. Schumacher, Leon G. and Jon Van Gerpen, "Research Needs Resulting from Experiences 
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58. Schumacher, Leon G. and Tabitha Madzura, "Lessons Learned While Fueling With 
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123. Reed, T. B., M. S. Graboski, and S. Gaur, "Development and Commercialization of 
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137. "Marketing Kentucky Grain Project" University of Kentucky (2003) 

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153. Ahouissoussi, Nicolas B.C. and Michael E. Wetzstein, "A Comparative Cost Analysis of 
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158. Weber, J. Alan and Donald L. Van Dyne, "Cost Implications of Feedstock Combinations 
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162. Campbell, John B., "New Markets for Bio-based Energy and Industrial Feedstocks: 
Biodiesel - Will There Be Enough," Presented at Agricultural Outlook Forum 2000, 
February 25, 2000, , 
Accessed on October 13, 2003. 

163. "Monthly Special Fuel Use Reported by States - 2001," Federal Highway Administration 
Web Page, l/mf33sf0 1 1 20 1 .htm Accessed 
on September 24, 2003. 

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